diff options
Diffstat (limited to 'src/ssl/test/runner/handshake_server.go')
-rw-r--r-- | src/ssl/test/runner/handshake_server.go | 964 |
1 files changed, 964 insertions, 0 deletions
diff --git a/src/ssl/test/runner/handshake_server.go b/src/ssl/test/runner/handshake_server.go new file mode 100644 index 0000000..1234a57 --- /dev/null +++ b/src/ssl/test/runner/handshake_server.go @@ -0,0 +1,964 @@ +// 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" + "crypto/ecdsa" + "crypto/elliptic" + "crypto/rsa" + "crypto/subtle" + "crypto/x509" + "encoding/asn1" + "errors" + "fmt" + "io" + "math/big" +) + +// serverHandshakeState contains details of a server handshake in progress. +// It's discarded once the handshake has completed. +type serverHandshakeState struct { + c *Conn + clientHello *clientHelloMsg + hello *serverHelloMsg + suite *cipherSuite + ellipticOk bool + ecdsaOk bool + sessionState *sessionState + finishedHash finishedHash + masterSecret []byte + certsFromClient [][]byte + cert *Certificate +} + +// serverHandshake performs a TLS handshake as a server. +func (c *Conn) serverHandshake() error { + config := c.config + + // If this is the first server handshake, we generate a random key to + // encrypt the tickets with. + config.serverInitOnce.Do(config.serverInit) + + c.sendHandshakeSeq = 0 + c.recvHandshakeSeq = 0 + + hs := serverHandshakeState{ + c: c, + } + isResume, err := hs.readClientHello() + if err != nil { + return err + } + + // For an overview of TLS handshaking, see https://tools.ietf.org/html/rfc5246#section-7.3 + if isResume { + // The client has included a session ticket and so we do an abbreviated handshake. + if err := hs.doResumeHandshake(); err != nil { + return err + } + if err := hs.establishKeys(); err != nil { + return err + } + if c.config.Bugs.RenewTicketOnResume { + if err := hs.sendSessionTicket(); err != nil { + return err + } + } + if err := hs.sendFinished(); err != nil { + return err + } + if err := hs.readFinished(isResume); err != nil { + return err + } + c.didResume = true + } else { + // The client didn't include a session ticket, or it wasn't + // valid so we do a full handshake. + if err := hs.doFullHandshake(); err != nil { + return err + } + if err := hs.establishKeys(); err != nil { + return err + } + if err := hs.readFinished(isResume); err != nil { + return err + } + if c.config.Bugs.ExpectFalseStart { + if err := c.readRecord(recordTypeApplicationData); err != nil { + return err + } + } + if err := hs.sendSessionTicket(); err != nil { + return err + } + if err := hs.sendFinished(); err != nil { + return err + } + } + c.handshakeComplete = true + + return nil +} + +// readClientHello reads a ClientHello message from the client and decides +// whether we will perform session resumption. +func (hs *serverHandshakeState) readClientHello() (isResume bool, err error) { + config := hs.c.config + c := hs.c + + msg, err := c.readHandshake() + if err != nil { + return false, err + } + var ok bool + hs.clientHello, ok = msg.(*clientHelloMsg) + if !ok { + c.sendAlert(alertUnexpectedMessage) + return false, unexpectedMessageError(hs.clientHello, msg) + } + if config.Bugs.RequireFastradioPadding && len(hs.clientHello.raw) < 1000 { + return false, errors.New("tls: ClientHello record size should be larger than 1000 bytes when padding enabled.") + } + + if c.isDTLS && !config.Bugs.SkipHelloVerifyRequest { + // Per RFC 6347, the version field in HelloVerifyRequest SHOULD + // be always DTLS 1.0 + helloVerifyRequest := &helloVerifyRequestMsg{ + vers: VersionTLS10, + cookie: make([]byte, 32), + } + if _, err := io.ReadFull(c.config.rand(), helloVerifyRequest.cookie); err != nil { + c.sendAlert(alertInternalError) + return false, errors.New("dtls: short read from Rand: " + err.Error()) + } + c.writeRecord(recordTypeHandshake, helloVerifyRequest.marshal()) + + msg, err := c.readHandshake() + if err != nil { + return false, err + } + newClientHello, ok := msg.(*clientHelloMsg) + if !ok { + c.sendAlert(alertUnexpectedMessage) + return false, unexpectedMessageError(hs.clientHello, msg) + } + if !bytes.Equal(newClientHello.cookie, helloVerifyRequest.cookie) { + return false, errors.New("dtls: invalid cookie") + } + + // Apart from the cookie, the two ClientHellos must + // match. Note that clientHello.equal compares the + // serialization, so we make a copy. + oldClientHelloCopy := *hs.clientHello + oldClientHelloCopy.raw = nil + oldClientHelloCopy.cookie = nil + newClientHelloCopy := *newClientHello + newClientHelloCopy.raw = nil + newClientHelloCopy.cookie = nil + if !oldClientHelloCopy.equal(&newClientHelloCopy) { + return false, errors.New("dtls: retransmitted ClientHello does not match") + } + hs.clientHello = newClientHello + } + + if config.Bugs.RequireSameRenegoClientVersion && c.clientVersion != 0 { + if c.clientVersion != hs.clientHello.vers { + return false, fmt.Errorf("tls: client offered different version on renego") + } + } + c.clientVersion = hs.clientHello.vers + + // Reject < 1.2 ClientHellos with signature_algorithms. + if c.clientVersion < VersionTLS12 && len(hs.clientHello.signatureAndHashes) > 0 { + return false, fmt.Errorf("tls: client included signature_algorithms before TLS 1.2") + } + + c.vers, ok = config.mutualVersion(hs.clientHello.vers) + if !ok { + c.sendAlert(alertProtocolVersion) + return false, fmt.Errorf("tls: client offered an unsupported, maximum protocol version of %x", hs.clientHello.vers) + } + c.haveVers = true + + hs.hello = new(serverHelloMsg) + hs.hello.isDTLS = c.isDTLS + + supportedCurve := false + preferredCurves := config.curvePreferences() +Curves: + for _, curve := range hs.clientHello.supportedCurves { + for _, supported := range preferredCurves { + if supported == curve { + supportedCurve = true + break Curves + } + } + } + + supportedPointFormat := false + for _, pointFormat := range hs.clientHello.supportedPoints { + if pointFormat == pointFormatUncompressed { + supportedPointFormat = true + break + } + } + hs.ellipticOk = supportedCurve && supportedPointFormat + + foundCompression := false + // We only support null compression, so check that the client offered it. + for _, compression := range hs.clientHello.compressionMethods { + if compression == compressionNone { + foundCompression = true + break + } + } + + if !foundCompression { + c.sendAlert(alertHandshakeFailure) + return false, errors.New("tls: client does not support uncompressed connections") + } + + hs.hello.vers = c.vers + hs.hello.random = make([]byte, 32) + _, err = io.ReadFull(config.rand(), hs.hello.random) + if err != nil { + c.sendAlert(alertInternalError) + return false, err + } + + if !bytes.Equal(c.clientVerify, hs.clientHello.secureRenegotiation) { + c.sendAlert(alertHandshakeFailure) + return false, errors.New("tls: renegotiation mismatch") + } + + if len(c.clientVerify) > 0 && !c.config.Bugs.EmptyRenegotiationInfo { + hs.hello.secureRenegotiation = append(hs.hello.secureRenegotiation, c.clientVerify...) + hs.hello.secureRenegotiation = append(hs.hello.secureRenegotiation, c.serverVerify...) + if c.config.Bugs.BadRenegotiationInfo { + hs.hello.secureRenegotiation[0] ^= 0x80 + } + } else { + hs.hello.secureRenegotiation = hs.clientHello.secureRenegotiation + } + + hs.hello.compressionMethod = compressionNone + hs.hello.duplicateExtension = c.config.Bugs.DuplicateExtension + if len(hs.clientHello.serverName) > 0 { + c.serverName = hs.clientHello.serverName + } + + if len(hs.clientHello.alpnProtocols) > 0 { + if selectedProto, fallback := mutualProtocol(hs.clientHello.alpnProtocols, c.config.NextProtos); !fallback { + hs.hello.alpnProtocol = selectedProto + c.clientProtocol = selectedProto + c.usedALPN = true + } + } else { + // Although sending an empty NPN extension is reasonable, Firefox has + // had a bug around this. Best to send nothing at all if + // config.NextProtos is empty. See + // https://code.google.com/p/go/issues/detail?id=5445. + if hs.clientHello.nextProtoNeg && len(config.NextProtos) > 0 { + hs.hello.nextProtoNeg = true + hs.hello.nextProtos = config.NextProtos + } + } + hs.hello.extendedMasterSecret = c.vers >= VersionTLS10 && hs.clientHello.extendedMasterSecret && !c.config.Bugs.NoExtendedMasterSecret + + if len(config.Certificates) == 0 { + c.sendAlert(alertInternalError) + return false, errors.New("tls: no certificates configured") + } + hs.cert = &config.Certificates[0] + if len(hs.clientHello.serverName) > 0 { + hs.cert = config.getCertificateForName(hs.clientHello.serverName) + } + if expected := c.config.Bugs.ExpectServerName; expected != "" && expected != hs.clientHello.serverName { + return false, errors.New("tls: unexpected server name") + } + + if hs.clientHello.channelIDSupported && config.RequestChannelID { + hs.hello.channelIDRequested = true + } + + if hs.clientHello.srtpProtectionProfiles != nil { + SRTPLoop: + for _, p1 := range c.config.SRTPProtectionProfiles { + for _, p2 := range hs.clientHello.srtpProtectionProfiles { + if p1 == p2 { + hs.hello.srtpProtectionProfile = p1 + c.srtpProtectionProfile = p1 + break SRTPLoop + } + } + } + } + + if c.config.Bugs.SendSRTPProtectionProfile != 0 { + hs.hello.srtpProtectionProfile = c.config.Bugs.SendSRTPProtectionProfile + } + + _, hs.ecdsaOk = hs.cert.PrivateKey.(*ecdsa.PrivateKey) + + if hs.checkForResumption() { + return true, nil + } + + var scsvFound bool + + for _, cipherSuite := range hs.clientHello.cipherSuites { + if cipherSuite == fallbackSCSV { + scsvFound = true + break + } + } + + if !scsvFound && config.Bugs.FailIfNotFallbackSCSV { + return false, errors.New("tls: no fallback SCSV found when expected") + } else if scsvFound && !config.Bugs.FailIfNotFallbackSCSV { + return false, errors.New("tls: fallback SCSV found when not expected") + } + + var preferenceList, supportedList []uint16 + if c.config.PreferServerCipherSuites { + preferenceList = c.config.cipherSuites() + supportedList = hs.clientHello.cipherSuites + } else { + preferenceList = hs.clientHello.cipherSuites + supportedList = c.config.cipherSuites() + } + + for _, id := range preferenceList { + if hs.suite = c.tryCipherSuite(id, supportedList, c.vers, hs.ellipticOk, hs.ecdsaOk); hs.suite != nil { + break + } + } + + if hs.suite == nil { + c.sendAlert(alertHandshakeFailure) + return false, errors.New("tls: no cipher suite supported by both client and server") + } + + return false, nil +} + +// checkForResumption returns true if we should perform resumption on this connection. +func (hs *serverHandshakeState) checkForResumption() bool { + c := hs.c + + if len(hs.clientHello.sessionTicket) > 0 { + if c.config.SessionTicketsDisabled { + return false + } + + var ok bool + if hs.sessionState, ok = c.decryptTicket(hs.clientHello.sessionTicket); !ok { + return false + } + } else { + if c.config.ServerSessionCache == nil { + return false + } + + var ok bool + sessionId := string(hs.clientHello.sessionId) + if hs.sessionState, ok = c.config.ServerSessionCache.Get(sessionId); !ok { + return false + } + } + + // Never resume a session for a different SSL version. + if !c.config.Bugs.AllowSessionVersionMismatch && c.vers != hs.sessionState.vers { + return false + } + + cipherSuiteOk := false + // Check that the client is still offering the ciphersuite in the session. + for _, id := range hs.clientHello.cipherSuites { + if id == hs.sessionState.cipherSuite { + cipherSuiteOk = true + break + } + } + if !cipherSuiteOk { + return false + } + + // Check that we also support the ciphersuite from the session. + hs.suite = c.tryCipherSuite(hs.sessionState.cipherSuite, c.config.cipherSuites(), hs.sessionState.vers, hs.ellipticOk, hs.ecdsaOk) + if hs.suite == nil { + return false + } + + sessionHasClientCerts := len(hs.sessionState.certificates) != 0 + needClientCerts := c.config.ClientAuth == RequireAnyClientCert || c.config.ClientAuth == RequireAndVerifyClientCert + if needClientCerts && !sessionHasClientCerts { + return false + } + if sessionHasClientCerts && c.config.ClientAuth == NoClientCert { + return false + } + + return true +} + +func (hs *serverHandshakeState) doResumeHandshake() error { + c := hs.c + + hs.hello.cipherSuite = hs.suite.id + // We echo the client's session ID in the ServerHello to let it know + // that we're doing a resumption. + hs.hello.sessionId = hs.clientHello.sessionId + hs.hello.ticketSupported = c.config.Bugs.RenewTicketOnResume + + hs.finishedHash = newFinishedHash(c.vers, hs.suite) + hs.finishedHash.discardHandshakeBuffer() + hs.writeClientHash(hs.clientHello.marshal()) + hs.writeServerHash(hs.hello.marshal()) + + c.writeRecord(recordTypeHandshake, hs.hello.marshal()) + + if len(hs.sessionState.certificates) > 0 { + if _, err := hs.processCertsFromClient(hs.sessionState.certificates); err != nil { + return err + } + } + + hs.masterSecret = hs.sessionState.masterSecret + c.extendedMasterSecret = hs.sessionState.extendedMasterSecret + + return nil +} + +func (hs *serverHandshakeState) doFullHandshake() error { + config := hs.c.config + c := hs.c + + isPSK := hs.suite.flags&suitePSK != 0 + if !isPSK && hs.clientHello.ocspStapling && len(hs.cert.OCSPStaple) > 0 { + hs.hello.ocspStapling = true + } + + if hs.clientHello.sctListSupported && len(hs.cert.SignedCertificateTimestampList) > 0 { + hs.hello.sctList = hs.cert.SignedCertificateTimestampList + } + + hs.hello.ticketSupported = hs.clientHello.ticketSupported && !config.SessionTicketsDisabled && c.vers > VersionSSL30 + hs.hello.cipherSuite = hs.suite.id + if config.Bugs.SendCipherSuite != 0 { + hs.hello.cipherSuite = config.Bugs.SendCipherSuite + } + c.extendedMasterSecret = hs.hello.extendedMasterSecret + + // Generate a session ID if we're to save the session. + if !hs.hello.ticketSupported && config.ServerSessionCache != nil { + hs.hello.sessionId = make([]byte, 32) + if _, err := io.ReadFull(config.rand(), hs.hello.sessionId); err != nil { + c.sendAlert(alertInternalError) + return errors.New("tls: short read from Rand: " + err.Error()) + } + } + + hs.finishedHash = newFinishedHash(c.vers, hs.suite) + hs.writeClientHash(hs.clientHello.marshal()) + hs.writeServerHash(hs.hello.marshal()) + + c.writeRecord(recordTypeHandshake, hs.hello.marshal()) + + if !isPSK { + certMsg := new(certificateMsg) + certMsg.certificates = hs.cert.Certificate + if !config.Bugs.UnauthenticatedECDH { + hs.writeServerHash(certMsg.marshal()) + c.writeRecord(recordTypeHandshake, certMsg.marshal()) + } + } + + if hs.hello.ocspStapling { + certStatus := new(certificateStatusMsg) + certStatus.statusType = statusTypeOCSP + certStatus.response = hs.cert.OCSPStaple + hs.writeServerHash(certStatus.marshal()) + c.writeRecord(recordTypeHandshake, certStatus.marshal()) + } + + keyAgreement := hs.suite.ka(c.vers) + skx, err := keyAgreement.generateServerKeyExchange(config, hs.cert, hs.clientHello, hs.hello) + if err != nil { + c.sendAlert(alertHandshakeFailure) + return err + } + if skx != nil && !config.Bugs.SkipServerKeyExchange { + hs.writeServerHash(skx.marshal()) + c.writeRecord(recordTypeHandshake, skx.marshal()) + } + + if config.ClientAuth >= RequestClientCert { + // Request a client certificate + certReq := &certificateRequestMsg{ + certificateTypes: config.ClientCertificateTypes, + } + if certReq.certificateTypes == nil { + certReq.certificateTypes = []byte{ + byte(CertTypeRSASign), + byte(CertTypeECDSASign), + } + } + if c.vers >= VersionTLS12 { + certReq.hasSignatureAndHash = true + if !config.Bugs.NoSignatureAndHashes { + certReq.signatureAndHashes = config.signatureAndHashesForServer() + } + } + + // An empty list of certificateAuthorities signals to + // the client that it may send any certificate in response + // to our request. When we know the CAs we trust, then + // we can send them down, so that the client can choose + // an appropriate certificate to give to us. + if config.ClientCAs != nil { + certReq.certificateAuthorities = config.ClientCAs.Subjects() + } + hs.writeServerHash(certReq.marshal()) + c.writeRecord(recordTypeHandshake, certReq.marshal()) + } + + helloDone := new(serverHelloDoneMsg) + hs.writeServerHash(helloDone.marshal()) + c.writeRecord(recordTypeHandshake, helloDone.marshal()) + + var pub crypto.PublicKey // public key for client auth, if any + + msg, err := c.readHandshake() + if err != nil { + return err + } + + var ok bool + // If we requested a client certificate, then the client must send a + // certificate message, even if it's empty. + if config.ClientAuth >= RequestClientCert { + var certMsg *certificateMsg + if certMsg, ok = msg.(*certificateMsg); !ok { + c.sendAlert(alertUnexpectedMessage) + return unexpectedMessageError(certMsg, msg) + } + hs.writeClientHash(certMsg.marshal()) + + if len(certMsg.certificates) == 0 { + // The client didn't actually send a certificate + switch config.ClientAuth { + case RequireAnyClientCert, RequireAndVerifyClientCert: + c.sendAlert(alertBadCertificate) + return errors.New("tls: client didn't provide a certificate") + } + } + + pub, err = hs.processCertsFromClient(certMsg.certificates) + if err != nil { + return err + } + + msg, err = c.readHandshake() + if err != nil { + return err + } + } + + // Get client key exchange + ckx, ok := msg.(*clientKeyExchangeMsg) + if !ok { + c.sendAlert(alertUnexpectedMessage) + return unexpectedMessageError(ckx, msg) + } + hs.writeClientHash(ckx.marshal()) + + preMasterSecret, err := keyAgreement.processClientKeyExchange(config, hs.cert, ckx, c.vers) + if err != nil { + c.sendAlert(alertHandshakeFailure) + return err + } + if c.extendedMasterSecret { + hs.masterSecret = extendedMasterFromPreMasterSecret(c.vers, hs.suite, preMasterSecret, hs.finishedHash) + } 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.clientHello.random, hs.hello.random) + } + + // If we received a client cert in response to our certificate request message, + // the client will send us a certificateVerifyMsg immediately after the + // clientKeyExchangeMsg. This message is a digest of all preceding + // handshake-layer messages that is signed using the private key corresponding + // to the client's certificate. This allows us to verify that the client is in + // possession of the private key of the certificate. + if len(c.peerCertificates) > 0 { + msg, err = c.readHandshake() + if err != nil { + return err + } + certVerify, ok := msg.(*certificateVerifyMsg) + if !ok { + c.sendAlert(alertUnexpectedMessage) + return unexpectedMessageError(certVerify, msg) + } + + // Determine the signature type. + var signatureAndHash signatureAndHash + if certVerify.hasSignatureAndHash { + signatureAndHash = certVerify.signatureAndHash + if !isSupportedSignatureAndHash(signatureAndHash, config.signatureAndHashesForServer()) { + return errors.New("tls: unsupported hash function for client certificate") + } + } else { + // Before TLS 1.2 the signature algorithm was implicit + // from the key type, and only one hash per signature + // algorithm was possible. Leave the hash as zero. + switch pub.(type) { + case *ecdsa.PublicKey: + signatureAndHash.signature = signatureECDSA + case *rsa.PublicKey: + signatureAndHash.signature = signatureRSA + } + } + + switch key := pub.(type) { + case *ecdsa.PublicKey: + if signatureAndHash.signature != signatureECDSA { + err = errors.New("tls: bad signature type for client's ECDSA certificate") + break + } + ecdsaSig := new(ecdsaSignature) + if _, err = asn1.Unmarshal(certVerify.signature, ecdsaSig); err != nil { + break + } + if ecdsaSig.R.Sign() <= 0 || ecdsaSig.S.Sign() <= 0 { + err = errors.New("ECDSA signature contained zero or negative values") + break + } + var digest []byte + digest, _, err = hs.finishedHash.hashForClientCertificate(signatureAndHash, hs.masterSecret) + if err != nil { + break + } + if !ecdsa.Verify(key, digest, ecdsaSig.R, ecdsaSig.S) { + err = errors.New("ECDSA verification failure") + break + } + case *rsa.PublicKey: + if signatureAndHash.signature != signatureRSA { + err = errors.New("tls: bad signature type for client's RSA certificate") + break + } + var digest []byte + var hashFunc crypto.Hash + digest, hashFunc, err = hs.finishedHash.hashForClientCertificate(signatureAndHash, hs.masterSecret) + if err != nil { + break + } + err = rsa.VerifyPKCS1v15(key, hashFunc, digest, certVerify.signature) + } + if err != nil { + c.sendAlert(alertBadCertificate) + return errors.New("could not validate signature of connection nonces: " + err.Error()) + } + + hs.writeClientHash(certVerify.marshal()) + } + + hs.finishedHash.discardHandshakeBuffer() + + return nil +} + +func (hs *serverHandshakeState) establishKeys() error { + c := hs.c + + clientMAC, serverMAC, clientKey, serverKey, clientIV, serverIV := + keysFromMasterSecret(c.vers, hs.suite, hs.masterSecret, hs.clientHello.random, hs.hello.random, hs.suite.macLen, hs.suite.keyLen, hs.suite.ivLen) + + var clientCipher, serverCipher interface{} + var clientHash, serverHash macFunction + + if hs.suite.aead == nil { + clientCipher = hs.suite.cipher(clientKey, clientIV, true /* for reading */) + clientHash = hs.suite.mac(c.vers, clientMAC) + serverCipher = hs.suite.cipher(serverKey, serverIV, false /* not 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, clientCipher, clientHash) + c.out.prepareCipherSpec(c.vers, serverCipher, serverHash) + + return nil +} + +func (hs *serverHandshakeState) readFinished(isResume bool) error { + c := hs.c + + c.readRecord(recordTypeChangeCipherSpec) + if err := c.in.error(); err != nil { + return err + } + + if hs.hello.nextProtoNeg { + msg, err := c.readHandshake() + if err != nil { + return err + } + nextProto, ok := msg.(*nextProtoMsg) + if !ok { + c.sendAlert(alertUnexpectedMessage) + return unexpectedMessageError(nextProto, msg) + } + hs.writeClientHash(nextProto.marshal()) + c.clientProtocol = nextProto.proto + } + + if hs.hello.channelIDRequested { + msg, err := c.readHandshake() + if err != nil { + return err + } + encryptedExtensions, ok := msg.(*encryptedExtensionsMsg) + if !ok { + c.sendAlert(alertUnexpectedMessage) + return unexpectedMessageError(encryptedExtensions, msg) + } + x := new(big.Int).SetBytes(encryptedExtensions.channelID[0:32]) + y := new(big.Int).SetBytes(encryptedExtensions.channelID[32:64]) + r := new(big.Int).SetBytes(encryptedExtensions.channelID[64:96]) + s := new(big.Int).SetBytes(encryptedExtensions.channelID[96:128]) + if !elliptic.P256().IsOnCurve(x, y) { + return errors.New("tls: invalid channel ID public key") + } + channelID := &ecdsa.PublicKey{elliptic.P256(), x, y} + var resumeHash []byte + if isResume { + resumeHash = hs.sessionState.handshakeHash + } + if !ecdsa.Verify(channelID, hs.finishedHash.hashForChannelID(resumeHash), r, s) { + return errors.New("tls: invalid channel ID signature") + } + c.channelID = channelID + + hs.writeClientHash(encryptedExtensions.marshal()) + } + + msg, err := c.readHandshake() + if err != nil { + return err + } + clientFinished, ok := msg.(*finishedMsg) + if !ok { + c.sendAlert(alertUnexpectedMessage) + return unexpectedMessageError(clientFinished, msg) + } + + verify := hs.finishedHash.clientSum(hs.masterSecret) + if len(verify) != len(clientFinished.verifyData) || + subtle.ConstantTimeCompare(verify, clientFinished.verifyData) != 1 { + c.sendAlert(alertHandshakeFailure) + return errors.New("tls: client's Finished message is incorrect") + } + c.clientVerify = append(c.clientVerify[:0], clientFinished.verifyData...) + + hs.writeClientHash(clientFinished.marshal()) + return nil +} + +func (hs *serverHandshakeState) sendSessionTicket() error { + c := hs.c + state := sessionState{ + vers: c.vers, + cipherSuite: hs.suite.id, + masterSecret: hs.masterSecret, + certificates: hs.certsFromClient, + handshakeHash: hs.finishedHash.server.Sum(nil), + } + + if !hs.hello.ticketSupported || hs.c.config.Bugs.SkipNewSessionTicket { + if c.config.ServerSessionCache != nil && len(hs.hello.sessionId) != 0 { + c.config.ServerSessionCache.Put(string(hs.hello.sessionId), &state) + } + return nil + } + + m := new(newSessionTicketMsg) + + var err error + m.ticket, err = c.encryptTicket(&state) + if err != nil { + return err + } + + hs.writeServerHash(m.marshal()) + c.writeRecord(recordTypeHandshake, m.marshal()) + + return nil +} + +func (hs *serverHandshakeState) sendFinished() error { + c := hs.c + + finished := new(finishedMsg) + finished.verifyData = hs.finishedHash.serverSum(hs.masterSecret) + c.serverVerify = append(c.serverVerify[:0], finished.verifyData...) + postCCSBytes := finished.marshal() + hs.writeServerHash(postCCSBytes) + + if c.config.Bugs.FragmentAcrossChangeCipherSpec { + c.writeRecord(recordTypeHandshake, postCCSBytes[:5]) + postCCSBytes = postCCSBytes[5:] + } + + if !c.config.Bugs.SkipChangeCipherSpec { + c.writeRecord(recordTypeChangeCipherSpec, []byte{1}) + } + + if c.config.Bugs.AppDataAfterChangeCipherSpec != nil { + c.writeRecord(recordTypeApplicationData, c.config.Bugs.AppDataAfterChangeCipherSpec) + } + + c.writeRecord(recordTypeHandshake, postCCSBytes) + + c.cipherSuite = hs.suite.id + + return nil +} + +// processCertsFromClient takes a chain of client certificates either from a +// Certificates message or from a sessionState and verifies them. It returns +// the public key of the leaf certificate. +func (hs *serverHandshakeState) processCertsFromClient(certificates [][]byte) (crypto.PublicKey, error) { + c := hs.c + + hs.certsFromClient = certificates + certs := make([]*x509.Certificate, len(certificates)) + var err error + for i, asn1Data := range certificates { + if certs[i], err = x509.ParseCertificate(asn1Data); err != nil { + c.sendAlert(alertBadCertificate) + return nil, errors.New("tls: failed to parse client certificate: " + err.Error()) + } + } + + if c.config.ClientAuth >= VerifyClientCertIfGiven && len(certs) > 0 { + opts := x509.VerifyOptions{ + Roots: c.config.ClientCAs, + CurrentTime: c.config.time(), + Intermediates: x509.NewCertPool(), + KeyUsages: []x509.ExtKeyUsage{x509.ExtKeyUsageClientAuth}, + } + + for _, cert := range certs[1:] { + opts.Intermediates.AddCert(cert) + } + + chains, err := certs[0].Verify(opts) + if err != nil { + c.sendAlert(alertBadCertificate) + return nil, errors.New("tls: failed to verify client's certificate: " + err.Error()) + } + + ok := false + for _, ku := range certs[0].ExtKeyUsage { + if ku == x509.ExtKeyUsageClientAuth { + ok = true + break + } + } + if !ok { + c.sendAlert(alertHandshakeFailure) + return nil, errors.New("tls: client's certificate's extended key usage doesn't permit it to be used for client authentication") + } + + c.verifiedChains = chains + } + + if len(certs) > 0 { + var pub crypto.PublicKey + switch key := certs[0].PublicKey.(type) { + case *ecdsa.PublicKey, *rsa.PublicKey: + pub = key + default: + c.sendAlert(alertUnsupportedCertificate) + return nil, fmt.Errorf("tls: client's certificate contains an unsupported public key of type %T", certs[0].PublicKey) + } + c.peerCertificates = certs + return pub, nil + } + + return nil, nil +} + +func (hs *serverHandshakeState) writeServerHash(msg []byte) { + // writeServerHash is called before writeRecord. + hs.writeHash(msg, hs.c.sendHandshakeSeq) +} + +func (hs *serverHandshakeState) writeClientHash(msg []byte) { + // writeClientHash is called after readHandshake. + hs.writeHash(msg, hs.c.recvHandshakeSeq-1) +} + +func (hs *serverHandshakeState) 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) + } +} + +// tryCipherSuite returns a cipherSuite with the given id if that cipher suite +// is acceptable to use. +func (c *Conn) tryCipherSuite(id uint16, supportedCipherSuites []uint16, version uint16, ellipticOk, ecdsaOk bool) *cipherSuite { + for _, supported := range supportedCipherSuites { + if id == supported { + var candidate *cipherSuite + + for _, s := range cipherSuites { + if s.id == id { + candidate = s + break + } + } + if candidate == nil { + continue + } + // Don't select a ciphersuite which we can't + // support for this client. + if (candidate.flags&suiteECDHE != 0) && !ellipticOk { + continue + } + if (candidate.flags&suiteECDSA != 0) != ecdsaOk { + continue + } + if !c.config.Bugs.SkipCipherVersionCheck && version < VersionTLS12 && candidate.flags&suiteTLS12 != 0 { + continue + } + if c.isDTLS && candidate.flags&suiteNoDTLS != 0 { + continue + } + return candidate + } + } + + return nil +} |