@@ -13,9 +13,20 @@ import (
"encoding/asn1"
"errors"
"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()
@@ -60,13 +71,58 @@ NextCipherSuite:
_, err := io.ReadFull(c.config.rand(), hello.random[4:])
if err != nil {
c.sendAlert(alertInternalError)
return errors.New("short read from Rand")
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()
@@ -86,25 +142,73 @@ NextCipherSuite:
c.vers = vers
c.haveVers = true
finishedHash := newFinishedHash(c.vers)
finishedHash.Write(hello.marshal())
finishedHash.Write(serverHello.marshal())
suite := mutualCipherSuite(c.config.cipherSuites(), serverHello.cipherSuite)
if suite == nil {
return c.sendAlert(alertHandshakeFailure)
}
if serverHello.compressionMethod != compressionNone {
return c.sendAlert(alertUnexpectedMessage)
hs := &clientHandshakeState{
c: c,
serverHello: serverHello,
hello: hello,
suite: suite,
finishedHash: newFinishedHash(c.vers),
session: session,
}
if !hello.nextProtoNeg && serverHello.nextProtoNeg {
c.sendAlert(alertHandshakeFailure)
return errors.New("server advertised unrequested NPN")
hs.finishedHash.Write(hs.hello.marshal())
hs.finishedHash.Write(hs.serverHello.marshal())
isResume, err := hs.processServerHello()
if err != nil {
return err
}
suite := mutualCipherSuite(c.config.cipherSuites(), serverHello.cipherSuite)
if suite == nil {
return c.sendAlert(alertHandshakeFailure)
if isResume {
if err := hs.establishKeys(); err != nil {
return err
}
if err := hs.readSessionTicket(); err != nil {
return err
}
if err := hs.readFinished(); err != nil {
return err
}
if err := hs.sendFinished(); 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(); err != nil {
return err
}
if err := hs.readSessionTicket(); err != nil {
return err
}
if err := hs.readFinished(); err != nil {
return err
}
}
msg, err = c.readHandshake()
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
}
@@ -112,7 +216,7 @@ NextCipherSuite:
if !ok || len(certMsg.certificates) == 0 {
return c.sendAlert(alertUnexpectedMessage)
}
finishedHash.Write(certMsg.marshal())
hs. finishedHash.Write(certMsg.marshal())
certs := make([]*x509.Certificate, len(certMsg.certificates))
for i, asn1Data := range certMsg.certificates {
@@ -154,7 +258,7 @@ NextCipherSuite:
c.peerCertificates = certs
if serverHello.ocspStapling {
if hs. serverHello.ocspStapling {
msg, err = c.readHandshake()
if err != nil {
return err
@@ -163,7 +267,7 @@ NextCipherSuite:
if !ok {
return c.sendAlert(alertUnexpectedMessage)
}
finishedHash.Write(cs.marshal())
hs. finishedHash.Write(cs.marshal())
if cs.statusType == statusTypeOCSP {
c.ocspResponse = cs.response
@@ -175,12 +279,12 @@ NextCipherSuite:
return err
}
keyAgreement := suite.ka(c.vers)
keyAgreement := hs. suite.ka(c.vers)
skx, ok := msg.(*serverKeyExchangeMsg)
if ok {
finishedHash.Write(skx.marshal())
err = keyAgreement.processServerKeyExchange(c.config, hello, serverHello, certs[0], skx)
hs. finishedHash.Write(skx.marshal())
err = keyAgreement.processServerKeyExchange(c.config, hs.h ello, hs. serverHello, certs[0], skx)
if err != nil {
c.sendAlert(alertUnexpectedMessage)
return err
@@ -209,7 +313,7 @@ NextCipherSuite:
// ClientCertificateType, unless there is some external
// arrangement to the contrary.
finishedHash.Write(certReq.marshal())
hs. finishedHash.Write(certReq.marshal())
var rsaAvail, ecdsaAvail bool
for _, certType := range certReq.certificateTypes {
@@ -274,7 +378,7 @@ NextCipherSuite:
if !ok {
return c.sendAlert(alertUnexpectedMessage)
}
finishedHash.Write(shd.marshal())
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
@@ -284,17 +388,17 @@ NextCipherSuite:
if chainToSend != nil {
certMsg.certificates = chainToSend.Certificate
}
finishedHash.Write(certMsg.marshal())
hs. finishedHash.Write(certMsg.marshal())
c.writeRecord(recordTypeHandshake, certMsg.marshal())
}
preMasterSecret, ckx, err := keyAgreement.generateClientKeyExchange(c.config, hello, certs[0])
preMasterSecret, ckx, err := keyAgreement.generateClientKeyExchange(c.config, hs.h ello, certs[0])
if err != nil {
c.sendAlert(alertInternalError)
return err
}
if ckx != nil {
finishedHash.Write(ckx.marshal())
hs. finishedHash.Write(ckx.marshal())
c.writeRecord(recordTypeHandshake, ckx.marshal())
}
@@ -306,7 +410,7 @@ NextCipherSuite:
switch key := c.config.Certificates[0].PrivateKey.(type) {
case *ecdsa.PrivateKey:
digest, _, hashId := finishedHash.hashForClientCertificate(signatureECDSA)
digest, _, hashId := hs. finishedHash.hashForClientCertificate(signatureECDSA)
r, s, err := ecdsa.Sign(c.config.rand(), key, digest)
if err == nil {
signed, err = asn1.Marshal(ecdsaSignature{r, s})
@@ -314,7 +418,7 @@ NextCipherSuite:
certVerify.signatureAndHash.signature = signatureECDSA
certVerify.signatureAndHash.hash = hashId
case *rsa.PrivateKey:
digest, hashFunc, hashId := finishedHash.hashForClientCertificate(signatureRSA)
digest, hashFunc, hashId := hs. finishedHash.hashForClientCertificate(signatureRSA)
signed, err = rsa.SignPKCS1v15(c.config.rand(), key, hashFunc, digest)
certVerify.signatureAndHash.signature = signatureRSA
certVerify.signatureAndHash.hash = hashId
@@ -326,56 +430,73 @@ NextCipherSuite:
}
certVerify.signature = signed
finishedHash.Write(certVerify.marshal())
hs. finishedHash.Write(certVerify.marshal())
c.writeRecord(recordTypeHandshake, certVerify.marshal())
}
masterSecret := masterFromPreMasterSecret(c.vers, preMasterSecret, hello.random, serverHello.random)
clientMAC, serverMAC, clientKey, serverKey, clientIV, serverIV :=
keysFromMasterSecret(c.vers, masterSecret, hello.random, serverHello.random, suite.macLen, suite.keyLen, suite.ivLen)
hs.masterSecret = masterFromPreMasterSecret(c.vers, preMasterSecret, hs.hello.random, hs.serverHello.random)
return nil
}
func (hs *clientHandshakeState) establishKeys() error {
c := hs.c
var clientCipher interface{}
var clientHash macFunction
if suite.cipher != nil {
clientCipher = suite.cipher(clientKey, clientIV, false /* not for reading */)
clientHash = suite.mac(c.vers, clientMAC)
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 = suite.aead(clientKey, clientIV)
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)
c.writeRecord(recordTypeChangeCipherSpec, []byte{1})
return nil
}
if serverHello.nextProtoNeg {
nextProto := new(nextProtoMsg)
proto, fallback := mutualProtocol(c.config.NextProtos, serverHello.nextProtos)
nextProto.proto = proto
c.clientProtocol = proto
c.clientProtocolFallback = fallback
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)
}
finishedHash.Write(nextProto.marshal())
c.writeRecord(recordTypeHandshake, nextProto.marshal())
func (hs *clientHandshakeState) processServerHello() (bool, error) {
c := hs.c
if hs.serverHello.compressionMethod != compressionNone {
return false, c.sendAlert(alertUnexpectedMessage)
}
finished := new(finishedMsg)
finished.verifyData = finishedHash.clientSum(masterSecret )
finishedHash.Write(finished.marshal() )
c.writeRecord(recordTypeHandshake, finished.marshal())
if !hs.hello.nextProtoNeg && hs.serverHello.nextProtoNeg {
c.sendAlert(alertHandshakeFailure )
return false, errors.New("server advertised unrequested NPN" )
}
var serverCipher interface{}
var serverHash macFunction
if suite.cipher != nil {
serverCipher = suite.cipher(serverKey, serverIV, true /* for reading */)
serverHash = suite.mac(c.vers, serverMAC)
} else {
serverCipher = suite.aead(serverKey, serverIV)
if hs.serverResumedSession() {
// Restore masterSecret and peerCerts from previous state
hs.masterSecret = hs.session.masterSecret
c.peerCertificates = hs.session.serverCertificates
return true, nil
}
c.in.prepareCipherSpec(c.vers, serverCipher, serverHash)
return false, nil
}
func (hs *clientHandshakeState) readFinished() error {
c := hs.c
c.readRecord(recordTypeChangeCipherSpec)
if err := c.error(); err != nil {
return err
}
msg, err = c.readHandshake()
msg, err : = c.readHandshake()
if err != nil {
return err
}
@@ -384,17 +505,73 @@ NextCipherSuite:
return c.sendAlert(alertUnexpectedMessage)
}
verify := finishedHash.serverSum(masterSecret)
verify := hs. finishedHash.serverSum(hs. masterSecret)
if len(verify) != len(serverFinished.verifyData) ||
subtle.ConstantTimeCompare(verify, serverFinished.verifyData) != 1 {
return c.sendAlert(alertHandshakeFailure)
}
hs.finishedHash.Write(serverFinished.marshal())
return nil
}
c.handshakeComplete = true
c.cipherSuite = suite.id
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 {
return c.sendAlert(alertUnexpectedMessage)
}
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() 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())
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 protocol given the
// set of client and server supported protocols. The set of client supported
// protocols must not be empty. It returns the resulting protocol and flag