1024 lines
30 KiB
Go
1024 lines
30 KiB
Go
// Copyright 2009 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package qtls
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import (
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"bytes"
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"crypto"
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"crypto/ecdsa"
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"crypto/rsa"
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"crypto/subtle"
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"crypto/x509"
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"errors"
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"fmt"
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"io"
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"net"
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"strconv"
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"strings"
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"sync/atomic"
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"time"
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)
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type clientHandshakeState struct {
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c *Conn
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serverHello *serverHelloMsg
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hello *clientHelloMsg
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suite *cipherSuite
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finishedHash finishedHash
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masterSecret []byte
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session *ClientSessionState
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}
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func (c *Conn) makeClientHello() (*clientHelloMsg, ecdheParameters, error) {
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config := c.config
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if len(config.ServerName) == 0 && !config.InsecureSkipVerify {
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return nil, nil, errors.New("tls: either ServerName or InsecureSkipVerify must be specified in the tls.Config")
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}
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nextProtosLength := 0
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for _, proto := range config.NextProtos {
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if l := len(proto); l == 0 || l > 255 {
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return nil, nil, errors.New("tls: invalid NextProtos value")
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} else {
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nextProtosLength += 1 + l
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}
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}
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if nextProtosLength > 0xffff {
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return nil, nil, errors.New("tls: NextProtos values too large")
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}
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supportedVersions := config.supportedVersions(true)
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if len(supportedVersions) == 0 {
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return nil, nil, errors.New("tls: no supported versions satisfy MinVersion and MaxVersion")
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}
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clientHelloVersion := supportedVersions[0]
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// The version at the beginning of the ClientHello was capped at TLS 1.2
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// for compatibility reasons. The supported_versions extension is used
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// to negotiate versions now. See RFC 8446, Section 4.2.1.
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if clientHelloVersion > VersionTLS12 {
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clientHelloVersion = VersionTLS12
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}
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hello := &clientHelloMsg{
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vers: clientHelloVersion,
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compressionMethods: []uint8{compressionNone},
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random: make([]byte, 32),
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sessionId: make([]byte, 32),
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ocspStapling: true,
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scts: true,
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serverName: hostnameInSNI(config.ServerName),
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supportedCurves: config.curvePreferences(),
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supportedPoints: []uint8{pointFormatUncompressed},
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nextProtoNeg: len(config.NextProtos) > 0,
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secureRenegotiationSupported: true,
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alpnProtocols: config.NextProtos,
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supportedVersions: supportedVersions,
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}
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if c.handshakes > 0 {
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hello.secureRenegotiation = c.clientFinished[:]
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}
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possibleCipherSuites := config.cipherSuites()
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hello.cipherSuites = make([]uint16, 0, len(possibleCipherSuites))
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NextCipherSuite:
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for _, suiteId := range possibleCipherSuites {
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for _, suite := range cipherSuites {
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if suite.id != suiteId {
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continue
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}
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// Don't advertise TLS 1.2-only cipher suites unless
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// we're attempting TLS 1.2.
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if hello.vers < VersionTLS12 && suite.flags&suiteTLS12 != 0 {
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continue
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}
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hello.cipherSuites = append(hello.cipherSuites, suiteId)
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continue NextCipherSuite
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}
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}
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_, err := io.ReadFull(config.rand(), hello.random)
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if err != nil {
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return nil, nil, errors.New("tls: short read from Rand: " + err.Error())
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}
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// A random session ID is used to detect when the server accepted a ticket
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// and is resuming a session (see RFC 5077). In TLS 1.3, it's always set as
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// a compatibility measure (see RFC 8446, Section 4.1.2).
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if _, err := io.ReadFull(config.rand(), hello.sessionId); err != nil {
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return nil, nil, errors.New("tls: short read from Rand: " + err.Error())
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}
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if hello.vers >= VersionTLS12 {
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hello.supportedSignatureAlgorithms = supportedSignatureAlgorithms
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}
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var params ecdheParameters
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if hello.supportedVersions[0] == VersionTLS13 {
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hello.cipherSuites = append(hello.cipherSuites, defaultCipherSuitesTLS13()...)
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curveID := config.curvePreferences()[0]
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if _, ok := curveForCurveID(curveID); curveID != X25519 && !ok {
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return nil, nil, errors.New("tls: CurvePreferences includes unsupported curve")
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}
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params, err = generateECDHEParameters(config.rand(), curveID)
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if err != nil {
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return nil, nil, err
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}
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hello.keyShares = []keyShare{{group: curveID, data: params.PublicKey()}}
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}
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if hello.supportedVersions[0] == VersionTLS13 && config.GetExtensions != nil {
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hello.additionalExtensions = config.GetExtensions(typeClientHello)
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}
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return hello, params, nil
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}
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func (c *Conn) clientHandshake() (err error) {
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if c.config == nil {
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c.config = defaultConfig()
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}
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c.setAlternativeRecordLayer()
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// This may be a renegotiation handshake, in which case some fields
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// need to be reset.
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c.didResume = false
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hello, ecdheParams, err := c.makeClientHello()
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if err != nil {
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return err
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}
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cacheKey, session, earlySecret, binderKey := c.loadSession(hello)
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if cacheKey != "" && session != nil {
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defer func() {
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// If we got a handshake failure when resuming a session, throw away
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// the session ticket. See RFC 5077, Section 3.2.
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//
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// RFC 8446 makes no mention of dropping tickets on failure, but it
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// does require servers to abort on invalid binders, so we need to
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// delete tickets to recover from a corrupted PSK.
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if err != nil {
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c.config.ClientSessionCache.Put(cacheKey, nil)
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}
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}()
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}
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if _, err := c.writeRecord(recordTypeHandshake, hello.marshal()); err != nil {
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return err
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}
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msg, err := c.readHandshake()
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if err != nil {
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return err
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}
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serverHello, ok := msg.(*serverHelloMsg)
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if !ok {
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c.sendAlert(alertUnexpectedMessage)
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return unexpectedMessageError(serverHello, msg)
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}
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if err := c.pickTLSVersion(serverHello); err != nil {
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return err
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}
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if c.vers == VersionTLS13 {
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hs := &clientHandshakeStateTLS13{
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c: c,
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serverHello: serverHello,
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hello: hello,
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ecdheParams: ecdheParams,
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session: session,
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earlySecret: earlySecret,
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binderKey: binderKey,
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}
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// In TLS 1.3, session tickets are delivered after the handshake.
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return hs.handshake()
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}
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hs := &clientHandshakeState{
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c: c,
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serverHello: serverHello,
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hello: hello,
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session: session,
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}
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if err := hs.handshake(); err != nil {
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return err
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}
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// If we had a successful handshake and hs.session is different from
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// the one already cached - cache a new one.
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if cacheKey != "" && hs.session != nil && session != hs.session {
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c.config.ClientSessionCache.Put(cacheKey, hs.session)
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}
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return nil
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}
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func (c *Conn) loadSession(hello *clientHelloMsg) (cacheKey string,
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session *ClientSessionState, earlySecret, binderKey []byte) {
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if c.config.SessionTicketsDisabled || c.config.ClientSessionCache == nil {
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return "", nil, nil, nil
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}
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hello.ticketSupported = true
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if hello.supportedVersions[0] == VersionTLS13 {
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// Require DHE on resumption as it guarantees forward secrecy against
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// compromise of the session ticket key. See RFC 8446, Section 4.2.9.
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hello.pskModes = []uint8{pskModeDHE}
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}
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// Session resumption is not allowed if renegotiating because
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// renegotiation is primarily used to allow a client to send a client
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// certificate, which would be skipped if session resumption occurred.
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if c.handshakes != 0 {
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return "", nil, nil, nil
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}
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// Try to resume a previously negotiated TLS session, if available.
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cacheKey = clientSessionCacheKey(c.conn.RemoteAddr(), c.config)
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session, ok := c.config.ClientSessionCache.Get(cacheKey)
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if !ok || session == nil {
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return cacheKey, nil, nil, nil
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}
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// Check that version used for the previous session is still valid.
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versOk := false
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for _, v := range hello.supportedVersions {
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if v == session.vers {
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versOk = true
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break
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}
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}
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if !versOk {
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return cacheKey, nil, nil, nil
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}
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// Check that the cached server certificate is not expired, and that it's
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// valid for the ServerName. This should be ensured by the cache key, but
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// protect the application from a faulty ClientSessionCache implementation.
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if !c.config.InsecureSkipVerify {
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if len(session.verifiedChains) == 0 {
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// The original connection had InsecureSkipVerify, while this doesn't.
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return cacheKey, nil, nil, nil
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}
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serverCert := session.serverCertificates[0]
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if c.config.time().After(serverCert.NotAfter) {
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// Expired certificate, delete the entry.
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c.config.ClientSessionCache.Put(cacheKey, nil)
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return cacheKey, nil, nil, nil
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}
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if err := serverCert.VerifyHostname(c.config.ServerName); err != nil {
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return cacheKey, nil, nil, nil
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}
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}
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if session.vers != VersionTLS13 {
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// In TLS 1.2 the cipher suite must match the resumed session. Ensure we
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// are still offering it.
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if mutualCipherSuite(hello.cipherSuites, session.cipherSuite) == nil {
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return cacheKey, nil, nil, nil
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}
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hello.sessionTicket = session.sessionTicket
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return
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}
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// Check that the session ticket is not expired.
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if c.config.time().After(session.useBy) {
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c.config.ClientSessionCache.Put(cacheKey, nil)
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return cacheKey, nil, nil, nil
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}
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// In TLS 1.3 the KDF hash must match the resumed session. Ensure we
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// offer at least one cipher suite with that hash.
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cipherSuite := cipherSuiteTLS13ByID(session.cipherSuite)
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if cipherSuite == nil {
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return cacheKey, nil, nil, nil
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}
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cipherSuiteOk := false
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for _, offeredID := range hello.cipherSuites {
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offeredSuite := cipherSuiteTLS13ByID(offeredID)
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if offeredSuite != nil && offeredSuite.hash == cipherSuite.hash {
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cipherSuiteOk = true
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break
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}
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}
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if !cipherSuiteOk {
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return cacheKey, nil, nil, nil
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}
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// Set the pre_shared_key extension. See RFC 8446, Section 4.2.11.1.
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ticketAge := uint32(c.config.time().Sub(session.receivedAt) / time.Millisecond)
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identity := pskIdentity{
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label: session.sessionTicket,
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obfuscatedTicketAge: ticketAge + session.ageAdd,
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}
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hello.pskIdentities = []pskIdentity{identity}
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hello.pskBinders = [][]byte{make([]byte, cipherSuite.hash.Size())}
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// Compute the PSK binders. See RFC 8446, Section 4.2.11.2.
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psk := cipherSuite.expandLabel(session.masterSecret, "resumption",
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session.nonce, cipherSuite.hash.Size())
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earlySecret = cipherSuite.extract(psk, nil)
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binderKey = cipherSuite.deriveSecret(earlySecret, resumptionBinderLabel, nil)
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transcript := cipherSuite.hash.New()
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transcript.Write(hello.marshalWithoutBinders())
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pskBinders := [][]byte{cipherSuite.finishedHash(binderKey, transcript)}
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hello.updateBinders(pskBinders)
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return
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}
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func (c *Conn) pickTLSVersion(serverHello *serverHelloMsg) error {
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peerVersion := serverHello.vers
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if serverHello.supportedVersion != 0 {
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peerVersion = serverHello.supportedVersion
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}
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vers, ok := c.config.mutualVersion(true, []uint16{peerVersion})
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if !ok {
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c.sendAlert(alertProtocolVersion)
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return fmt.Errorf("tls: server selected unsupported protocol version %x", peerVersion)
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}
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c.vers = vers
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c.haveVers = true
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c.in.version = vers
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c.out.version = vers
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return nil
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}
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// Does the handshake, either a full one or resumes old session. Requires hs.c,
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// hs.hello, hs.serverHello, and, optionally, hs.session to be set.
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func (hs *clientHandshakeState) handshake() error {
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c := hs.c
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isResume, err := hs.processServerHello()
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if err != nil {
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return err
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}
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hs.finishedHash = newFinishedHash(c.vers, hs.suite)
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// No signatures of the handshake are needed in a resumption.
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// Otherwise, in a full handshake, if we don't have any certificates
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// configured then we will never send a CertificateVerify message and
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// thus no signatures are needed in that case either.
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if isResume || (len(c.config.Certificates) == 0 && c.config.GetClientCertificate == nil) {
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hs.finishedHash.discardHandshakeBuffer()
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}
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hs.finishedHash.Write(hs.hello.marshal())
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hs.finishedHash.Write(hs.serverHello.marshal())
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c.buffering = true
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if isResume {
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if err := hs.establishKeys(); err != nil {
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return err
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}
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if err := hs.readSessionTicket(); err != nil {
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return err
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}
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if err := hs.readFinished(c.serverFinished[:]); err != nil {
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return err
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}
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c.clientFinishedIsFirst = false
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if err := hs.sendFinished(c.clientFinished[:]); err != nil {
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return err
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}
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if _, err := c.flush(); err != nil {
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return err
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}
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} else {
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if err := hs.doFullHandshake(); err != nil {
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return err
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}
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if err := hs.establishKeys(); err != nil {
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return err
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}
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if err := hs.sendFinished(c.clientFinished[:]); err != nil {
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return err
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}
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if _, err := c.flush(); err != nil {
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return err
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}
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c.clientFinishedIsFirst = true
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if err := hs.readSessionTicket(); err != nil {
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return err
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}
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if err := hs.readFinished(c.serverFinished[:]); err != nil {
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return err
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}
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}
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c.ekm = ekmFromMasterSecret(c.vers, hs.suite, hs.masterSecret, hs.hello.random, hs.serverHello.random)
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c.didResume = isResume
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atomic.StoreUint32(&c.handshakeStatus, 1)
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return nil
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}
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func (hs *clientHandshakeState) pickCipherSuite() error {
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if hs.suite = mutualCipherSuite(hs.hello.cipherSuites, hs.serverHello.cipherSuite); hs.suite == nil {
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hs.c.sendAlert(alertHandshakeFailure)
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return errors.New("tls: server chose an unconfigured cipher suite")
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}
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hs.c.cipherSuite = hs.suite.id
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return nil
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}
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func (hs *clientHandshakeState) doFullHandshake() error {
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c := hs.c
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msg, err := c.readHandshake()
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if err != nil {
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return err
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}
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certMsg, ok := msg.(*certificateMsg)
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if !ok || len(certMsg.certificates) == 0 {
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c.sendAlert(alertUnexpectedMessage)
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return unexpectedMessageError(certMsg, msg)
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}
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hs.finishedHash.Write(certMsg.marshal())
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if c.handshakes == 0 {
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// If this is the first handshake on a connection, process and
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// (optionally) verify the server's certificates.
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if err := c.verifyServerCertificate(certMsg.certificates); err != nil {
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return err
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}
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} else {
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// This is a renegotiation handshake. We require that the
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// server's identity (i.e. leaf certificate) is unchanged and
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// thus any previous trust decision is still valid.
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//
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// See https://mitls.org/pages/attacks/3SHAKE for the
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// motivation behind this requirement.
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if !bytes.Equal(c.peerCertificates[0].Raw, certMsg.certificates[0]) {
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c.sendAlert(alertBadCertificate)
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return errors.New("tls: server's identity changed during renegotiation")
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}
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}
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msg, err = c.readHandshake()
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if err != nil {
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return err
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}
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cs, ok := msg.(*certificateStatusMsg)
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if ok {
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// RFC4366 on Certificate Status Request:
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// The server MAY return a "certificate_status" message.
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if !hs.serverHello.ocspStapling {
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// If a server returns a "CertificateStatus" message, then the
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// server MUST have included an extension of type "status_request"
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// with empty "extension_data" in the extended server hello.
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c.sendAlert(alertUnexpectedMessage)
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return errors.New("tls: received unexpected CertificateStatus message")
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}
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hs.finishedHash.Write(cs.marshal())
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c.ocspResponse = cs.response
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msg, err = c.readHandshake()
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if err != nil {
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return err
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}
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}
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keyAgreement := hs.suite.ka(c.vers)
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skx, ok := msg.(*serverKeyExchangeMsg)
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if ok {
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hs.finishedHash.Write(skx.marshal())
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err = keyAgreement.processServerKeyExchange(c.config, hs.hello, hs.serverHello, c.peerCertificates[0], skx)
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if err != nil {
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c.sendAlert(alertUnexpectedMessage)
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return err
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}
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msg, err = c.readHandshake()
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if err != nil {
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return err
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}
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}
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var chainToSend *Certificate
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var certRequested bool
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certReq, ok := msg.(*certificateRequestMsg)
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if ok {
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certRequested = true
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hs.finishedHash.Write(certReq.marshal())
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cri := certificateRequestInfoFromMsg(certReq)
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if chainToSend, err = c.getClientCertificate(cri); err != nil {
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c.sendAlert(alertInternalError)
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return err
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}
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msg, err = c.readHandshake()
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if err != nil {
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return err
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}
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|
}
|
|
|
|
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)
|
|
certMsg.certificates = chainToSend.Certificate
|
|
hs.finishedHash.Write(certMsg.marshal())
|
|
if _, err := c.writeRecord(recordTypeHandshake, certMsg.marshal()); err != nil {
|
|
return err
|
|
}
|
|
}
|
|
|
|
preMasterSecret, ckx, err := keyAgreement.generateClientKeyExchange(c.config, hs.hello, c.peerCertificates[0])
|
|
if err != nil {
|
|
c.sendAlert(alertInternalError)
|
|
return err
|
|
}
|
|
if ckx != nil {
|
|
hs.finishedHash.Write(ckx.marshal())
|
|
if _, err := c.writeRecord(recordTypeHandshake, ckx.marshal()); err != nil {
|
|
return err
|
|
}
|
|
}
|
|
|
|
if chainToSend != nil && len(chainToSend.Certificate) > 0 {
|
|
certVerify := &certificateVerifyMsg{
|
|
hasSignatureAlgorithm: 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)
|
|
}
|
|
|
|
signatureAlgorithm, sigType, hashFunc, err := pickSignatureAlgorithm(key.Public(), certReq.supportedSignatureAlgorithms, hs.hello.supportedSignatureAlgorithms, c.vers)
|
|
if err != nil {
|
|
c.sendAlert(alertInternalError)
|
|
return err
|
|
}
|
|
// SignatureAndHashAlgorithm was introduced in TLS 1.2.
|
|
if certVerify.hasSignatureAlgorithm {
|
|
certVerify.signatureAlgorithm = signatureAlgorithm
|
|
}
|
|
digest, err := hs.finishedHash.hashForClientCertificate(sigType, hashFunc, hs.masterSecret)
|
|
if err != nil {
|
|
c.sendAlert(alertInternalError)
|
|
return err
|
|
}
|
|
signOpts := crypto.SignerOpts(hashFunc)
|
|
if sigType == signatureRSAPSS {
|
|
signOpts = &rsa.PSSOptions{SaltLength: rsa.PSSSaltLengthEqualsHash, Hash: hashFunc}
|
|
}
|
|
certVerify.signature, err = key.Sign(c.config.rand(), digest, signOpts)
|
|
if err != nil {
|
|
c.sendAlert(alertInternalError)
|
|
return err
|
|
}
|
|
|
|
hs.finishedHash.Write(certVerify.marshal())
|
|
if _, err := c.writeRecord(recordTypeHandshake, certVerify.marshal()); err != nil {
|
|
return err
|
|
}
|
|
}
|
|
|
|
hs.masterSecret = masterFromPreMasterSecret(c.vers, hs.suite, preMasterSecret, hs.hello.random, hs.serverHello.random)
|
|
if err := c.config.writeKeyLog(keyLogLabelTLS12, hs.hello.random, hs.masterSecret); err != nil {
|
|
c.sendAlert(alertInternalError)
|
|
return errors.New("tls: failed to write to key log: " + err.Error())
|
|
}
|
|
|
|
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 err := hs.pickCipherSuite(); err != nil {
|
|
return false, err
|
|
}
|
|
|
|
if hs.serverHello.compressionMethod != compressionNone {
|
|
c.sendAlert(alertUnexpectedMessage)
|
|
return false, errors.New("tls: server selected unsupported compression format")
|
|
}
|
|
|
|
if c.handshakes == 0 && hs.serverHello.secureRenegotiationSupported {
|
|
c.secureRenegotiation = true
|
|
if len(hs.serverHello.secureRenegotiation) != 0 {
|
|
c.sendAlert(alertHandshakeFailure)
|
|
return false, errors.New("tls: initial handshake had non-empty renegotiation extension")
|
|
}
|
|
}
|
|
|
|
if c.handshakes > 0 && c.secureRenegotiation {
|
|
var expectedSecureRenegotiation [24]byte
|
|
copy(expectedSecureRenegotiation[:], c.clientFinished[:])
|
|
copy(expectedSecureRenegotiation[12:], c.serverFinished[:])
|
|
if !bytes.Equal(hs.serverHello.secureRenegotiation, expectedSecureRenegotiation[:]) {
|
|
c.sendAlert(alertHandshakeFailure)
|
|
return false, errors.New("tls: incorrect renegotiation extension contents")
|
|
}
|
|
}
|
|
|
|
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("tls: server advertised unrequested NPN extension")
|
|
}
|
|
|
|
if !clientDidALPN && serverHasALPN {
|
|
c.sendAlert(alertHandshakeFailure)
|
|
return false, errors.New("tls: server advertised unrequested ALPN extension")
|
|
}
|
|
|
|
if serverHasNPN && serverHasALPN {
|
|
c.sendAlert(alertHandshakeFailure)
|
|
return false, errors.New("tls: server advertised both NPN and ALPN extensions")
|
|
}
|
|
|
|
if serverHasALPN {
|
|
c.clientProtocol = hs.serverHello.alpnProtocol
|
|
c.clientProtocolFallback = false
|
|
}
|
|
c.scts = hs.serverHello.scts
|
|
|
|
if !hs.serverResumedSession() {
|
|
return false, nil
|
|
}
|
|
|
|
if hs.session.vers != c.vers {
|
|
c.sendAlert(alertHandshakeFailure)
|
|
return false, errors.New("tls: server resumed a session with a different version")
|
|
}
|
|
|
|
if hs.session.cipherSuite != hs.suite.id {
|
|
c.sendAlert(alertHandshakeFailure)
|
|
return false, errors.New("tls: server resumed a session with a different cipher suite")
|
|
}
|
|
|
|
// Restore masterSecret and peerCerts from previous state
|
|
hs.masterSecret = hs.session.masterSecret
|
|
c.peerCertificates = hs.session.serverCertificates
|
|
c.verifiedChains = hs.session.verifiedChains
|
|
return true, nil
|
|
}
|
|
|
|
func (hs *clientHandshakeState) readFinished(out []byte) error {
|
|
c := hs.c
|
|
|
|
if err := c.readChangeCipherSpec(); 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,
|
|
verifiedChains: c.verifiedChains,
|
|
receivedAt: c.config.time(),
|
|
}
|
|
|
|
return nil
|
|
}
|
|
|
|
func (hs *clientHandshakeState) sendFinished(out []byte) error {
|
|
c := hs.c
|
|
|
|
if _, err := c.writeRecord(recordTypeChangeCipherSpec, []byte{1}); err != nil {
|
|
return err
|
|
}
|
|
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())
|
|
if _, err := c.writeRecord(recordTypeHandshake, nextProto.marshal()); err != nil {
|
|
return err
|
|
}
|
|
}
|
|
|
|
finished := new(finishedMsg)
|
|
finished.verifyData = hs.finishedHash.clientSum(hs.masterSecret)
|
|
hs.finishedHash.Write(finished.marshal())
|
|
if _, err := c.writeRecord(recordTypeHandshake, finished.marshal()); err != nil {
|
|
return err
|
|
}
|
|
copy(out, finished.verifyData)
|
|
return nil
|
|
}
|
|
|
|
// verifyServerCertificate parses and verifies the provided chain, setting
|
|
// c.verifiedChains and c.peerCertificates or sending the appropriate alert.
|
|
func (c *Conn) verifyServerCertificate(certificates [][]byte) error {
|
|
certs := make([]*x509.Certificate, len(certificates))
|
|
for i, asn1Data := range 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)
|
|
}
|
|
var err error
|
|
c.verifiedChains, err = certs[0].Verify(opts)
|
|
if err != nil {
|
|
c.sendAlert(alertBadCertificate)
|
|
return err
|
|
}
|
|
}
|
|
|
|
if c.config.VerifyPeerCertificate != nil {
|
|
if err := c.config.VerifyPeerCertificate(certificates, c.verifiedChains); 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
|
|
|
|
return nil
|
|
}
|
|
|
|
// tls11SignatureSchemes contains the signature schemes that we synthesise for
|
|
// a TLS <= 1.1 connection, based on the supported certificate types.
|
|
var (
|
|
tls11SignatureSchemes = []SignatureScheme{ECDSAWithP256AndSHA256, ECDSAWithP384AndSHA384, ECDSAWithP521AndSHA512, PKCS1WithSHA256, PKCS1WithSHA384, PKCS1WithSHA512, PKCS1WithSHA1}
|
|
tls11SignatureSchemesECDSA = tls11SignatureSchemes[:3]
|
|
tls11SignatureSchemesRSA = tls11SignatureSchemes[3:]
|
|
)
|
|
|
|
// certificateRequestInfoFromMsg generates a CertificateRequestInfo from a TLS
|
|
// <= 1.2 CertificateRequest, making an effort to fill in missing information.
|
|
func certificateRequestInfoFromMsg(certReq *certificateRequestMsg) *CertificateRequestInfo {
|
|
var rsaAvail, ecdsaAvail bool
|
|
for _, certType := range certReq.certificateTypes {
|
|
switch certType {
|
|
case certTypeRSASign:
|
|
rsaAvail = true
|
|
case certTypeECDSASign:
|
|
ecdsaAvail = true
|
|
}
|
|
}
|
|
|
|
cri := &CertificateRequestInfo{
|
|
AcceptableCAs: certReq.certificateAuthorities,
|
|
}
|
|
|
|
if !certReq.hasSignatureAlgorithm {
|
|
// Prior to TLS 1.2, the signature schemes were not
|
|
// included in the certificate request message. In this
|
|
// case we use a plausible list based on the acceptable
|
|
// certificate types.
|
|
switch {
|
|
case rsaAvail && ecdsaAvail:
|
|
cri.SignatureSchemes = tls11SignatureSchemes
|
|
case rsaAvail:
|
|
cri.SignatureSchemes = tls11SignatureSchemesRSA
|
|
case ecdsaAvail:
|
|
cri.SignatureSchemes = tls11SignatureSchemesECDSA
|
|
}
|
|
return cri
|
|
}
|
|
|
|
// In TLS 1.2, the signature schemes apply to both the certificate chain and
|
|
// the leaf key, while the certificate types only apply to the leaf key.
|
|
// See RFC 5246, Section 7.4.4 (where it calls this "somewhat complicated").
|
|
// Filter the signature schemes based on the certificate type.
|
|
cri.SignatureSchemes = make([]SignatureScheme, 0, len(certReq.supportedSignatureAlgorithms))
|
|
for _, sigScheme := range certReq.supportedSignatureAlgorithms {
|
|
switch signatureFromSignatureScheme(sigScheme) {
|
|
case signatureECDSA:
|
|
if ecdsaAvail {
|
|
cri.SignatureSchemes = append(cri.SignatureSchemes, sigScheme)
|
|
}
|
|
case signatureRSAPSS, signaturePKCS1v15:
|
|
if rsaAvail {
|
|
cri.SignatureSchemes = append(cri.SignatureSchemes, sigScheme)
|
|
}
|
|
}
|
|
}
|
|
|
|
return cri
|
|
}
|
|
|
|
func (c *Conn) getClientCertificate(cri *CertificateRequestInfo) (*Certificate, error) {
|
|
if c.config.GetClientCertificate != nil {
|
|
return c.config.GetClientCertificate(cri)
|
|
}
|
|
|
|
// We need to search our list of client certs for one
|
|
// where SignatureAlgorithm is acceptable to the server and the
|
|
// Issuer is in AcceptableCAs.
|
|
for i, chain := range c.config.Certificates {
|
|
sigOK := false
|
|
for _, alg := range signatureSchemesForCertificate(c.vers, &chain) {
|
|
if isSupportedSignatureAlgorithm(alg, cri.SignatureSchemes) {
|
|
sigOK = true
|
|
break
|
|
}
|
|
}
|
|
if !sigOK {
|
|
continue
|
|
}
|
|
|
|
if len(cri.AcceptableCAs) == 0 {
|
|
return &chain, nil
|
|
}
|
|
|
|
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 {
|
|
var err error
|
|
if x509Cert, err = x509.ParseCertificate(cert); err != nil {
|
|
c.sendAlert(alertInternalError)
|
|
return nil, errors.New("tls: failed to parse configured certificate chain #" + strconv.Itoa(i) + ": " + err.Error())
|
|
}
|
|
}
|
|
|
|
for _, ca := range cri.AcceptableCAs {
|
|
if bytes.Equal(x509Cert.RawIssuer, ca) {
|
|
return &chain, nil
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
// No acceptable certificate found. Don't send a certificate.
|
|
return new(Certificate), 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
|
|
}
|
|
|
|
// hostnameInSNI converts name into an approriate hostname for SNI.
|
|
// Literal IP addresses and absolute FQDNs are not permitted as SNI values.
|
|
// See RFC 6066, Section 3.
|
|
func hostnameInSNI(name string) string {
|
|
host := name
|
|
if len(host) > 0 && host[0] == '[' && host[len(host)-1] == ']' {
|
|
host = host[1 : len(host)-1]
|
|
}
|
|
if i := strings.LastIndex(host, "%"); i > 0 {
|
|
host = host[:i]
|
|
}
|
|
if net.ParseIP(host) != nil {
|
|
return ""
|
|
}
|
|
for len(name) > 0 && name[len(name)-1] == '.' {
|
|
name = name[:len(name)-1]
|
|
}
|
|
return name
|
|
}
|