d0d532f169
This is generally much cleaner and makes it possible to implement the more lax cipher matching in draft 18. BUG=117 Change-Id: I595d7619d60bc92e598d75b43945286323c0b72b Reviewed-on: https://boringssl-review.googlesource.com/12309 Reviewed-by: Nick Harper <nharper@chromium.org> Reviewed-by: David Benjamin <davidben@google.com> Commit-Queue: David Benjamin <davidben@google.com> CQ-Verified: CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org>
1916 lines
57 KiB
Go
1916 lines
57 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 runner
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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/elliptic"
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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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"math/big"
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"time"
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)
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// serverHandshakeState contains details of a server handshake in progress.
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// It's discarded once the handshake has completed.
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type serverHandshakeState struct {
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c *Conn
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clientHello *clientHelloMsg
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hello *serverHelloMsg
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suite *cipherSuite
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ellipticOk bool
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ecdsaOk bool
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sessionState *sessionState
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finishedHash finishedHash
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masterSecret []byte
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certsFromClient [][]byte
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cert *Certificate
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finishedBytes []byte
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}
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// serverHandshake performs a TLS handshake as a server.
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func (c *Conn) serverHandshake() error {
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config := c.config
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// If this is the first server handshake, we generate a random key to
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// encrypt the tickets with.
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config.serverInitOnce.Do(config.serverInit)
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c.sendHandshakeSeq = 0
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c.recvHandshakeSeq = 0
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hs := serverHandshakeState{
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c: c,
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}
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if err := hs.readClientHello(); err != nil {
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return err
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}
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if c.vers >= VersionTLS13 {
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if err := hs.doTLS13Handshake(); err != nil {
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return err
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}
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} else {
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isResume, err := hs.processClientHello()
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if err != nil {
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return err
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}
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// For an overview of TLS handshaking, see https://tools.ietf.org/html/rfc5246#section-7.3
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if isResume {
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// The client has included a session ticket and so we do an abbreviated handshake.
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if err := hs.doResumeHandshake(); 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 c.config.Bugs.RenewTicketOnResume {
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if err := hs.sendSessionTicket(); err != nil {
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return err
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}
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}
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if err := hs.sendFinished(c.firstFinished[:]); err != nil {
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return err
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}
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// Most retransmits are triggered by a timeout, but the final
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// leg of the handshake is retransmited upon re-receiving a
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// Finished.
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if err := c.simulatePacketLoss(func() {
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c.sendHandshakeSeq--
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c.writeRecord(recordTypeHandshake, hs.finishedBytes)
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c.flushHandshake()
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}); err != nil {
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return err
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}
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if err := hs.readFinished(nil, isResume); err != nil {
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return err
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}
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c.didResume = true
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} else {
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// The client didn't include a session ticket, or it wasn't
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// valid so we do a full handshake.
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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.readFinished(c.firstFinished[:], isResume); err != nil {
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return err
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}
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if c.config.Bugs.AlertBeforeFalseStartTest != 0 {
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c.sendAlert(c.config.Bugs.AlertBeforeFalseStartTest)
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}
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if c.config.Bugs.ExpectFalseStart {
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if err := c.readRecord(recordTypeApplicationData); err != nil {
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return fmt.Errorf("tls: peer did not false start: %s", err)
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}
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}
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if err := hs.sendSessionTicket(); err != nil {
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return err
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}
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if err := hs.sendFinished(nil); err != nil {
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return err
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}
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}
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c.exporterSecret = hs.masterSecret
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}
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c.handshakeComplete = true
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copy(c.clientRandom[:], hs.clientHello.random)
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copy(c.serverRandom[:], hs.hello.random)
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return nil
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}
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// readClientHello reads a ClientHello message from the client and determines
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// the protocol version.
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func (hs *serverHandshakeState) readClientHello() error {
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config := hs.c.config
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c := hs.c
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if err := c.simulatePacketLoss(nil); 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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var ok bool
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hs.clientHello, ok = msg.(*clientHelloMsg)
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if !ok {
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c.sendAlert(alertUnexpectedMessage)
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return unexpectedMessageError(hs.clientHello, msg)
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}
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if size := config.Bugs.RequireClientHelloSize; size != 0 && len(hs.clientHello.raw) != size {
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return fmt.Errorf("tls: ClientHello record size is %d, but expected %d", len(hs.clientHello.raw), size)
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}
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if c.isDTLS && !config.Bugs.SkipHelloVerifyRequest {
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// Per RFC 6347, the version field in HelloVerifyRequest SHOULD
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// be always DTLS 1.0
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helloVerifyRequest := &helloVerifyRequestMsg{
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vers: versionToWire(VersionTLS10, c.isDTLS),
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cookie: make([]byte, 32),
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}
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if _, err := io.ReadFull(c.config.rand(), helloVerifyRequest.cookie); err != nil {
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c.sendAlert(alertInternalError)
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return errors.New("dtls: short read from Rand: " + err.Error())
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}
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c.writeRecord(recordTypeHandshake, helloVerifyRequest.marshal())
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c.flushHandshake()
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if err := c.simulatePacketLoss(nil); 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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newClientHello, ok := msg.(*clientHelloMsg)
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if !ok {
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c.sendAlert(alertUnexpectedMessage)
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return unexpectedMessageError(hs.clientHello, msg)
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}
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if !bytes.Equal(newClientHello.cookie, helloVerifyRequest.cookie) {
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return errors.New("dtls: invalid cookie")
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}
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// Apart from the cookie, the two ClientHellos must
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// match. Note that clientHello.equal compares the
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// serialization, so we make a copy.
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oldClientHelloCopy := *hs.clientHello
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oldClientHelloCopy.raw = nil
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oldClientHelloCopy.cookie = nil
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newClientHelloCopy := *newClientHello
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newClientHelloCopy.raw = nil
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newClientHelloCopy.cookie = nil
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if !oldClientHelloCopy.equal(&newClientHelloCopy) {
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return errors.New("dtls: retransmitted ClientHello does not match")
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}
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hs.clientHello = newClientHello
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}
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if config.Bugs.RequireSameRenegoClientVersion && c.clientVersion != 0 {
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if c.clientVersion != hs.clientHello.vers {
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return fmt.Errorf("tls: client offered different version on renego")
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}
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}
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c.clientVersion = hs.clientHello.vers
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// Convert the ClientHello wire version to a protocol version.
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var clientVersion uint16
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if c.isDTLS {
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if hs.clientHello.vers <= 0xfefd {
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clientVersion = VersionTLS12
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} else if hs.clientHello.vers <= 0xfeff {
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clientVersion = VersionTLS10
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}
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} else {
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if hs.clientHello.vers >= VersionTLS12 {
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clientVersion = VersionTLS12
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} else if hs.clientHello.vers >= VersionTLS11 {
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clientVersion = VersionTLS11
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} else if hs.clientHello.vers >= VersionTLS10 {
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clientVersion = VersionTLS10
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} else if hs.clientHello.vers >= VersionSSL30 {
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clientVersion = VersionSSL30
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}
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}
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if config.Bugs.NegotiateVersion != 0 {
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c.vers = config.Bugs.NegotiateVersion
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} else if c.haveVers && config.Bugs.NegotiateVersionOnRenego != 0 {
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c.vers = config.Bugs.NegotiateVersionOnRenego
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} else if len(hs.clientHello.supportedVersions) > 0 {
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// Use the versions extension if supplied.
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var foundVersion, foundGREASE bool
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for _, extVersion := range hs.clientHello.supportedVersions {
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if isGREASEValue(extVersion) {
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foundGREASE = true
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}
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extVersion, ok = wireToVersion(extVersion, c.isDTLS)
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if !ok {
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continue
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}
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if config.isSupportedVersion(extVersion, c.isDTLS) && !foundVersion {
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c.vers = extVersion
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foundVersion = true
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break
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}
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}
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if !foundVersion {
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c.sendAlert(alertProtocolVersion)
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return errors.New("tls: client did not offer any supported protocol versions")
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}
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if config.Bugs.ExpectGREASE && !foundGREASE {
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return errors.New("tls: no GREASE version value found")
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}
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} else {
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// Otherwise, use the legacy ClientHello version.
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version := clientVersion
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if maxVersion := config.maxVersion(c.isDTLS); version > maxVersion {
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version = maxVersion
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}
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if version == 0 || !config.isSupportedVersion(version, c.isDTLS) {
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return fmt.Errorf("tls: client offered an unsupported, maximum protocol version of %x", hs.clientHello.vers)
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}
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c.vers = version
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}
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c.haveVers = true
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// Reject < 1.2 ClientHellos with signature_algorithms.
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if clientVersion < VersionTLS12 && len(hs.clientHello.signatureAlgorithms) > 0 {
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return fmt.Errorf("tls: client included signature_algorithms before TLS 1.2")
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}
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// Check the client cipher list is consistent with the version.
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if clientVersion < VersionTLS12 {
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for _, id := range hs.clientHello.cipherSuites {
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if isTLS12Cipher(id) {
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return fmt.Errorf("tls: client offered TLS 1.2 cipher before TLS 1.2")
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}
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}
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}
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if config.Bugs.ExpectNoTLS12Session {
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if len(hs.clientHello.sessionId) > 0 {
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return fmt.Errorf("tls: client offered an unexpected session ID")
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}
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if len(hs.clientHello.sessionTicket) > 0 {
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return fmt.Errorf("tls: client offered an unexpected session ticket")
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}
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}
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if config.Bugs.ExpectNoTLS13PSK && len(hs.clientHello.pskIdentities) > 0 {
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return fmt.Errorf("tls: client offered unexpected PSK identities")
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}
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var scsvFound, greaseFound bool
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for _, cipherSuite := range hs.clientHello.cipherSuites {
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if cipherSuite == fallbackSCSV {
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scsvFound = true
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}
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if isGREASEValue(cipherSuite) {
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greaseFound = true
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}
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}
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if !scsvFound && config.Bugs.FailIfNotFallbackSCSV {
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return errors.New("tls: no fallback SCSV found when expected")
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} else if scsvFound && !config.Bugs.FailIfNotFallbackSCSV {
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return errors.New("tls: fallback SCSV found when not expected")
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}
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if !greaseFound && config.Bugs.ExpectGREASE {
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return errors.New("tls: no GREASE cipher suite value found")
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}
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greaseFound = false
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for _, curve := range hs.clientHello.supportedCurves {
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if isGREASEValue(uint16(curve)) {
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greaseFound = true
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break
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}
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}
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if !greaseFound && config.Bugs.ExpectGREASE {
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return errors.New("tls: no GREASE curve value found")
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}
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if len(hs.clientHello.keyShares) > 0 {
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greaseFound = false
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for _, keyShare := range hs.clientHello.keyShares {
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if isGREASEValue(uint16(keyShare.group)) {
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greaseFound = true
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break
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}
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}
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if !greaseFound && config.Bugs.ExpectGREASE {
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return errors.New("tls: no GREASE curve value found")
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}
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}
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if config.Bugs.IgnorePeerSignatureAlgorithmPreferences {
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hs.clientHello.signatureAlgorithms = config.signSignatureAlgorithms()
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}
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if config.Bugs.IgnorePeerCurvePreferences {
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hs.clientHello.supportedCurves = config.curvePreferences()
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}
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if config.Bugs.IgnorePeerCipherPreferences {
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hs.clientHello.cipherSuites = config.cipherSuites()
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}
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return nil
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}
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func (hs *serverHandshakeState) doTLS13Handshake() error {
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c := hs.c
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config := c.config
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hs.hello = &serverHelloMsg{
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isDTLS: c.isDTLS,
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vers: versionToWire(c.vers, c.isDTLS),
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versOverride: config.Bugs.SendServerHelloVersion,
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customExtension: config.Bugs.CustomUnencryptedExtension,
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unencryptedALPN: config.Bugs.SendUnencryptedALPN,
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}
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hs.hello.random = make([]byte, 32)
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if _, err := io.ReadFull(config.rand(), hs.hello.random); err != nil {
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c.sendAlert(alertInternalError)
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return err
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}
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// TLS 1.3 forbids clients from advertising any non-null compression.
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if len(hs.clientHello.compressionMethods) != 1 || hs.clientHello.compressionMethods[0] != compressionNone {
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return errors.New("tls: client sent compression method other than null for TLS 1.3")
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}
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// Prepare an EncryptedExtensions message, but do not send it yet.
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encryptedExtensions := new(encryptedExtensionsMsg)
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encryptedExtensions.empty = config.Bugs.EmptyEncryptedExtensions
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if err := hs.processClientExtensions(&encryptedExtensions.extensions); err != nil {
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return err
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}
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// Select the cipher suite.
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var preferenceList, supportedList []uint16
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if config.PreferServerCipherSuites {
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preferenceList = config.cipherSuites()
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supportedList = hs.clientHello.cipherSuites
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} else {
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preferenceList = hs.clientHello.cipherSuites
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supportedList = config.cipherSuites()
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}
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for _, id := range preferenceList {
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if hs.suite = c.tryCipherSuite(id, supportedList, c.vers, true, true); hs.suite != nil {
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break
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}
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}
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if hs.suite == nil {
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c.sendAlert(alertHandshakeFailure)
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return errors.New("tls: no cipher suite supported by both client and server")
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}
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hs.hello.cipherSuite = hs.suite.id
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if c.config.Bugs.SendCipherSuite != 0 {
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hs.hello.cipherSuite = c.config.Bugs.SendCipherSuite
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}
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hs.finishedHash = newFinishedHash(c.vers, hs.suite)
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hs.finishedHash.discardHandshakeBuffer()
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hs.writeClientHash(hs.clientHello.marshal())
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supportedCurve := false
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var selectedCurve CurveID
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preferredCurves := config.curvePreferences()
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Curves:
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for _, curve := range hs.clientHello.supportedCurves {
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for _, supported := range preferredCurves {
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if supported == curve {
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supportedCurve = true
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selectedCurve = curve
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break Curves
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}
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}
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}
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if !supportedCurve {
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c.sendAlert(alertHandshakeFailure)
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return errors.New("tls: no curve supported by both client and server")
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}
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pskIdentities := hs.clientHello.pskIdentities
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pskKEModes := hs.clientHello.pskKEModes
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if len(pskIdentities) == 0 && len(hs.clientHello.sessionTicket) > 0 && c.config.Bugs.AcceptAnySession {
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psk := pskIdentity{
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ticket: hs.clientHello.sessionTicket,
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}
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pskIdentities = []pskIdentity{psk}
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pskKEModes = []byte{pskDHEKEMode}
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}
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var pskIndex int
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foundKEMode := bytes.IndexByte(pskKEModes, pskDHEKEMode) >= 0
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if foundKEMode {
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for i, pskIdentity := range pskIdentities {
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// TODO(svaldez): Check the obfuscatedTicketAge before accepting 0-RTT.
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sessionState, ok := c.decryptTicket(pskIdentity.ticket)
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if !ok {
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continue
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}
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|
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if !config.Bugs.AcceptAnySession {
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if sessionState.vers != c.vers {
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continue
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}
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if sessionState.ticketExpiration.Before(c.config.time()) {
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continue
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}
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if sessionState.cipherSuite != hs.suite.id {
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continue
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}
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}
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|
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clientTicketAge := time.Duration(uint32(pskIdentity.obfuscatedTicketAge-sessionState.ticketAgeAdd)) * time.Millisecond
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if config.Bugs.ExpectTicketAge != 0 && clientTicketAge != config.Bugs.ExpectTicketAge {
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c.sendAlert(alertHandshakeFailure)
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return errors.New("tls: invalid ticket age")
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}
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|
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hs.sessionState = sessionState
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hs.hello.hasPSKIdentity = true
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hs.hello.pskIdentity = uint16(i)
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pskIndex = i
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if config.Bugs.SelectPSKIdentityOnResume != 0 {
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hs.hello.pskIdentity = config.Bugs.SelectPSKIdentityOnResume
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}
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c.didResume = true
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break
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}
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}
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|
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if config.Bugs.AlwaysSelectPSKIdentity {
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hs.hello.hasPSKIdentity = true
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hs.hello.pskIdentity = 0
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}
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|
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// Verify the PSK binder. Note there may not be a PSK binder if
|
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// AcceptAnyBinder is set. See https://crbug.com/boringssl/115.
|
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if hs.sessionState != nil && !config.Bugs.AcceptAnySession {
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binderToVerify := hs.clientHello.pskBinders[pskIndex]
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if err := verifyPSKBinder(hs.clientHello, hs.sessionState, binderToVerify, []byte{}); err != nil {
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return err
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}
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}
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|
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// Resolve PSK and compute the early secret.
|
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var psk []byte
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if hs.sessionState != nil {
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psk = hs.sessionState.masterSecret
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} else {
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psk = hs.finishedHash.zeroSecret()
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}
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|
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earlySecret := hs.finishedHash.extractKey(hs.finishedHash.zeroSecret(), psk)
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|
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hs.hello.hasKeyShare = true
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if hs.sessionState != nil && config.Bugs.NegotiatePSKResumption {
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hs.hello.hasKeyShare = false
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}
|
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if config.Bugs.MissingKeyShare {
|
|
hs.hello.hasKeyShare = false
|
|
}
|
|
|
|
firstHelloRetryRequest := true
|
|
|
|
ResendHelloRetryRequest:
|
|
var sendHelloRetryRequest bool
|
|
helloRetryRequest := &helloRetryRequestMsg{
|
|
vers: versionToWire(c.vers, c.isDTLS),
|
|
duplicateExtensions: config.Bugs.DuplicateHelloRetryRequestExtensions,
|
|
}
|
|
|
|
if config.Bugs.AlwaysSendHelloRetryRequest {
|
|
sendHelloRetryRequest = true
|
|
}
|
|
|
|
if config.Bugs.SendHelloRetryRequestCookie != nil {
|
|
sendHelloRetryRequest = true
|
|
helloRetryRequest.cookie = config.Bugs.SendHelloRetryRequestCookie
|
|
}
|
|
|
|
if len(config.Bugs.CustomHelloRetryRequestExtension) > 0 {
|
|
sendHelloRetryRequest = true
|
|
helloRetryRequest.customExtension = config.Bugs.CustomHelloRetryRequestExtension
|
|
}
|
|
|
|
var selectedKeyShare *keyShareEntry
|
|
if hs.hello.hasKeyShare {
|
|
// Look for the key share corresponding to our selected curve.
|
|
for i := range hs.clientHello.keyShares {
|
|
if hs.clientHello.keyShares[i].group == selectedCurve {
|
|
selectedKeyShare = &hs.clientHello.keyShares[i]
|
|
break
|
|
}
|
|
}
|
|
|
|
if config.Bugs.ExpectMissingKeyShare && selectedKeyShare != nil {
|
|
return errors.New("tls: expected missing key share")
|
|
}
|
|
|
|
if selectedKeyShare == nil {
|
|
helloRetryRequest.hasSelectedGroup = true
|
|
helloRetryRequest.selectedGroup = selectedCurve
|
|
sendHelloRetryRequest = true
|
|
}
|
|
}
|
|
|
|
if config.Bugs.SendHelloRetryRequestCurve != 0 {
|
|
helloRetryRequest.hasSelectedGroup = true
|
|
helloRetryRequest.selectedGroup = config.Bugs.SendHelloRetryRequestCurve
|
|
sendHelloRetryRequest = true
|
|
}
|
|
|
|
if config.Bugs.SkipHelloRetryRequest {
|
|
sendHelloRetryRequest = false
|
|
}
|
|
|
|
if sendHelloRetryRequest {
|
|
oldClientHelloBytes := hs.clientHello.marshal()
|
|
hs.writeServerHash(helloRetryRequest.marshal())
|
|
c.writeRecord(recordTypeHandshake, helloRetryRequest.marshal())
|
|
c.flushHandshake()
|
|
|
|
// Read new ClientHello.
|
|
newMsg, err := c.readHandshake()
|
|
if err != nil {
|
|
return err
|
|
}
|
|
newClientHello, ok := newMsg.(*clientHelloMsg)
|
|
if !ok {
|
|
c.sendAlert(alertUnexpectedMessage)
|
|
return unexpectedMessageError(newClientHello, newMsg)
|
|
}
|
|
hs.writeClientHash(newClientHello.marshal())
|
|
|
|
// Check that the new ClientHello matches the old ClientHello,
|
|
// except for relevant modifications.
|
|
//
|
|
// TODO(davidben): Make this check more precise.
|
|
oldClientHelloCopy := *hs.clientHello
|
|
oldClientHelloCopy.raw = nil
|
|
oldClientHelloCopy.hasEarlyData = false
|
|
newClientHelloCopy := *newClientHello
|
|
newClientHelloCopy.raw = nil
|
|
|
|
if helloRetryRequest.hasSelectedGroup {
|
|
newKeyShares := newClientHelloCopy.keyShares
|
|
if len(newKeyShares) != 1 || newKeyShares[0].group != helloRetryRequest.selectedGroup {
|
|
return errors.New("tls: KeyShare from HelloRetryRequest not in new ClientHello")
|
|
}
|
|
selectedKeyShare = &newKeyShares[0]
|
|
newClientHelloCopy.keyShares = oldClientHelloCopy.keyShares
|
|
}
|
|
|
|
if len(helloRetryRequest.cookie) > 0 {
|
|
if !bytes.Equal(newClientHelloCopy.tls13Cookie, helloRetryRequest.cookie) {
|
|
return errors.New("tls: cookie from HelloRetryRequest not present in new ClientHello")
|
|
}
|
|
newClientHelloCopy.tls13Cookie = nil
|
|
}
|
|
|
|
// PSK binders and obfuscated ticket age are both updated in the
|
|
// second ClientHello.
|
|
if len(oldClientHelloCopy.pskIdentities) != len(newClientHelloCopy.pskIdentities) {
|
|
return errors.New("tls: PSK identity count from old and new ClientHello do not match")
|
|
}
|
|
for i, identity := range oldClientHelloCopy.pskIdentities {
|
|
newClientHelloCopy.pskIdentities[i].obfuscatedTicketAge = identity.obfuscatedTicketAge
|
|
}
|
|
newClientHelloCopy.pskBinders = oldClientHelloCopy.pskBinders
|
|
|
|
if !oldClientHelloCopy.equal(&newClientHelloCopy) {
|
|
return errors.New("tls: new ClientHello does not match")
|
|
}
|
|
|
|
if firstHelloRetryRequest && config.Bugs.SecondHelloRetryRequest {
|
|
firstHelloRetryRequest = false
|
|
goto ResendHelloRetryRequest
|
|
}
|
|
|
|
// Verify the PSK binder. Note there may not be a PSK binder if
|
|
// AcceptAnyBinder is set. See https://crbug.com/115.
|
|
if hs.sessionState != nil && !config.Bugs.AcceptAnySession {
|
|
binderToVerify := newClientHello.pskBinders[pskIndex]
|
|
err := verifyPSKBinder(newClientHello, hs.sessionState, binderToVerify, append(oldClientHelloBytes, helloRetryRequest.marshal()...))
|
|
if err != nil {
|
|
return err
|
|
}
|
|
}
|
|
}
|
|
|
|
// Resolve ECDHE and compute the handshake secret.
|
|
var ecdheSecret []byte
|
|
if hs.hello.hasKeyShare {
|
|
// Once a curve has been selected and a key share identified,
|
|
// the server needs to generate a public value and send it in
|
|
// the ServerHello.
|
|
curve, ok := curveForCurveID(selectedCurve)
|
|
if !ok {
|
|
panic("tls: server failed to look up curve ID")
|
|
}
|
|
c.curveID = selectedCurve
|
|
|
|
var peerKey []byte
|
|
if config.Bugs.SkipHelloRetryRequest {
|
|
// If skipping HelloRetryRequest, use a random key to
|
|
// avoid crashing.
|
|
curve2, _ := curveForCurveID(selectedCurve)
|
|
var err error
|
|
peerKey, err = curve2.offer(config.rand())
|
|
if err != nil {
|
|
return err
|
|
}
|
|
} else {
|
|
peerKey = selectedKeyShare.keyExchange
|
|
}
|
|
|
|
var publicKey []byte
|
|
var err error
|
|
publicKey, ecdheSecret, err = curve.accept(config.rand(), peerKey)
|
|
if err != nil {
|
|
c.sendAlert(alertHandshakeFailure)
|
|
return err
|
|
}
|
|
hs.hello.hasKeyShare = true
|
|
|
|
curveID := selectedCurve
|
|
if c.config.Bugs.SendCurve != 0 {
|
|
curveID = config.Bugs.SendCurve
|
|
}
|
|
if c.config.Bugs.InvalidECDHPoint {
|
|
publicKey[0] ^= 0xff
|
|
}
|
|
|
|
hs.hello.keyShare = keyShareEntry{
|
|
group: curveID,
|
|
keyExchange: publicKey,
|
|
}
|
|
|
|
if config.Bugs.EncryptedExtensionsWithKeyShare {
|
|
encryptedExtensions.extensions.hasKeyShare = true
|
|
encryptedExtensions.extensions.keyShare = keyShareEntry{
|
|
group: curveID,
|
|
keyExchange: publicKey,
|
|
}
|
|
}
|
|
} else {
|
|
ecdheSecret = hs.finishedHash.zeroSecret()
|
|
}
|
|
|
|
// Send unencrypted ServerHello.
|
|
hs.writeServerHash(hs.hello.marshal())
|
|
if config.Bugs.PartialEncryptedExtensionsWithServerHello {
|
|
helloBytes := hs.hello.marshal()
|
|
toWrite := make([]byte, 0, len(helloBytes)+1)
|
|
toWrite = append(toWrite, helloBytes...)
|
|
toWrite = append(toWrite, typeEncryptedExtensions)
|
|
c.writeRecord(recordTypeHandshake, toWrite)
|
|
} else {
|
|
c.writeRecord(recordTypeHandshake, hs.hello.marshal())
|
|
}
|
|
c.flushHandshake()
|
|
|
|
// Compute the handshake secret.
|
|
handshakeSecret := hs.finishedHash.extractKey(earlySecret, ecdheSecret)
|
|
|
|
// Switch to handshake traffic keys.
|
|
serverHandshakeTrafficSecret := hs.finishedHash.deriveSecret(handshakeSecret, serverHandshakeTrafficLabel)
|
|
c.out.useTrafficSecret(c.vers, hs.suite, serverHandshakeTrafficSecret, serverWrite)
|
|
clientHandshakeTrafficSecret := hs.finishedHash.deriveSecret(handshakeSecret, clientHandshakeTrafficLabel)
|
|
c.in.useTrafficSecret(c.vers, hs.suite, clientHandshakeTrafficSecret, clientWrite)
|
|
|
|
// Send EncryptedExtensions.
|
|
hs.writeServerHash(encryptedExtensions.marshal())
|
|
if config.Bugs.PartialEncryptedExtensionsWithServerHello {
|
|
// The first byte has already been sent.
|
|
c.writeRecord(recordTypeHandshake, encryptedExtensions.marshal()[1:])
|
|
} else {
|
|
c.writeRecord(recordTypeHandshake, encryptedExtensions.marshal())
|
|
}
|
|
|
|
if hs.sessionState == nil {
|
|
if config.ClientAuth >= RequestClientCert {
|
|
// Request a client certificate
|
|
certReq := &certificateRequestMsg{
|
|
hasSignatureAlgorithm: true,
|
|
hasRequestContext: true,
|
|
requestContext: config.Bugs.SendRequestContext,
|
|
}
|
|
if !config.Bugs.NoSignatureAlgorithms {
|
|
certReq.signatureAlgorithms = config.verifySignatureAlgorithms()
|
|
}
|
|
|
|
// 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())
|
|
}
|
|
|
|
certMsg := &certificateMsg{
|
|
hasRequestContext: true,
|
|
}
|
|
if !config.Bugs.EmptyCertificateList {
|
|
for i, certData := range hs.cert.Certificate {
|
|
cert := certificateEntry{
|
|
data: certData,
|
|
}
|
|
if i == 0 {
|
|
if hs.clientHello.ocspStapling {
|
|
cert.ocspResponse = hs.cert.OCSPStaple
|
|
}
|
|
if hs.clientHello.sctListSupported {
|
|
cert.sctList = hs.cert.SignedCertificateTimestampList
|
|
}
|
|
cert.duplicateExtensions = config.Bugs.SendDuplicateCertExtensions
|
|
cert.extraExtension = config.Bugs.SendExtensionOnCertificate
|
|
} else {
|
|
if config.Bugs.SendOCSPOnIntermediates != nil {
|
|
cert.ocspResponse = config.Bugs.SendOCSPOnIntermediates
|
|
}
|
|
if config.Bugs.SendSCTOnIntermediates != nil {
|
|
cert.sctList = config.Bugs.SendSCTOnIntermediates
|
|
}
|
|
}
|
|
certMsg.certificates = append(certMsg.certificates, cert)
|
|
}
|
|
}
|
|
certMsgBytes := certMsg.marshal()
|
|
hs.writeServerHash(certMsgBytes)
|
|
c.writeRecord(recordTypeHandshake, certMsgBytes)
|
|
|
|
certVerify := &certificateVerifyMsg{
|
|
hasSignatureAlgorithm: true,
|
|
}
|
|
|
|
// Determine the hash to sign.
|
|
privKey := hs.cert.PrivateKey
|
|
|
|
var err error
|
|
certVerify.signatureAlgorithm, err = selectSignatureAlgorithm(c.vers, privKey, config, hs.clientHello.signatureAlgorithms)
|
|
if err != nil {
|
|
c.sendAlert(alertInternalError)
|
|
return err
|
|
}
|
|
|
|
input := hs.finishedHash.certificateVerifyInput(serverCertificateVerifyContextTLS13)
|
|
certVerify.signature, err = signMessage(c.vers, privKey, c.config, certVerify.signatureAlgorithm, input)
|
|
if err != nil {
|
|
c.sendAlert(alertInternalError)
|
|
return err
|
|
}
|
|
|
|
if config.Bugs.SendSignatureAlgorithm != 0 {
|
|
certVerify.signatureAlgorithm = config.Bugs.SendSignatureAlgorithm
|
|
}
|
|
|
|
hs.writeServerHash(certVerify.marshal())
|
|
c.writeRecord(recordTypeHandshake, certVerify.marshal())
|
|
} else if hs.sessionState != nil {
|
|
// Pick up certificates from the session instead.
|
|
if len(hs.sessionState.certificates) > 0 {
|
|
if _, err := hs.processCertsFromClient(hs.sessionState.certificates); err != nil {
|
|
return err
|
|
}
|
|
}
|
|
}
|
|
|
|
finished := new(finishedMsg)
|
|
finished.verifyData = hs.finishedHash.serverSum(serverHandshakeTrafficSecret)
|
|
if config.Bugs.BadFinished {
|
|
finished.verifyData[0]++
|
|
}
|
|
hs.writeServerHash(finished.marshal())
|
|
c.writeRecord(recordTypeHandshake, finished.marshal())
|
|
if c.config.Bugs.SendExtraFinished {
|
|
c.writeRecord(recordTypeHandshake, finished.marshal())
|
|
}
|
|
c.flushHandshake()
|
|
|
|
// The various secrets do not incorporate the client's final leg, so
|
|
// derive them now before updating the handshake context.
|
|
masterSecret := hs.finishedHash.extractKey(handshakeSecret, hs.finishedHash.zeroSecret())
|
|
clientTrafficSecret := hs.finishedHash.deriveSecret(masterSecret, clientApplicationTrafficLabel)
|
|
serverTrafficSecret := hs.finishedHash.deriveSecret(masterSecret, serverApplicationTrafficLabel)
|
|
c.exporterSecret = hs.finishedHash.deriveSecret(masterSecret, exporterLabel)
|
|
|
|
// Switch to application data keys on write. In particular, any alerts
|
|
// from the client certificate are sent over these keys.
|
|
c.out.useTrafficSecret(c.vers, hs.suite, serverTrafficSecret, serverWrite)
|
|
|
|
// If we requested a client certificate, then the client must send a
|
|
// certificate message, even if it's empty.
|
|
if config.ClientAuth >= RequestClientCert {
|
|
msg, err := c.readHandshake()
|
|
if err != nil {
|
|
return err
|
|
}
|
|
|
|
certMsg, ok := msg.(*certificateMsg)
|
|
if !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(alertCertificateRequired)
|
|
return errors.New("tls: client didn't provide a certificate")
|
|
}
|
|
}
|
|
|
|
var certs [][]byte
|
|
for _, cert := range certMsg.certificates {
|
|
certs = append(certs, cert.data)
|
|
// OCSP responses and SCT lists are not negotiated in
|
|
// client certificates.
|
|
if cert.ocspResponse != nil || cert.sctList != nil {
|
|
c.sendAlert(alertUnsupportedExtension)
|
|
return errors.New("tls: unexpected extensions in the client certificate")
|
|
}
|
|
}
|
|
pub, err := hs.processCertsFromClient(certs)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
|
|
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)
|
|
}
|
|
|
|
c.peerSignatureAlgorithm = certVerify.signatureAlgorithm
|
|
input := hs.finishedHash.certificateVerifyInput(clientCertificateVerifyContextTLS13)
|
|
if err := verifyMessage(c.vers, pub, config, certVerify.signatureAlgorithm, input, certVerify.signature); err != nil {
|
|
c.sendAlert(alertBadCertificate)
|
|
return err
|
|
}
|
|
hs.writeClientHash(certVerify.marshal())
|
|
}
|
|
}
|
|
|
|
if encryptedExtensions.extensions.channelIDRequested {
|
|
msg, err := c.readHandshake()
|
|
if err != nil {
|
|
return err
|
|
}
|
|
channelIDMsg, ok := msg.(*channelIDMsg)
|
|
if !ok {
|
|
c.sendAlert(alertUnexpectedMessage)
|
|
return unexpectedMessageError(channelIDMsg, msg)
|
|
}
|
|
channelIDHash := crypto.SHA256.New()
|
|
channelIDHash.Write(hs.finishedHash.certificateVerifyInput(channelIDContextTLS13))
|
|
channelID, err := verifyChannelIDMessage(channelIDMsg, channelIDHash.Sum(nil))
|
|
if err != nil {
|
|
return err
|
|
}
|
|
c.channelID = channelID
|
|
|
|
hs.writeClientHash(channelIDMsg.marshal())
|
|
}
|
|
|
|
// Read the client Finished message.
|
|
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(clientHandshakeTrafficSecret)
|
|
if len(verify) != len(clientFinished.verifyData) ||
|
|
subtle.ConstantTimeCompare(verify, clientFinished.verifyData) != 1 {
|
|
c.sendAlert(alertHandshakeFailure)
|
|
return errors.New("tls: client's Finished message was incorrect")
|
|
}
|
|
hs.writeClientHash(clientFinished.marshal())
|
|
|
|
// Switch to application data keys on read.
|
|
c.in.useTrafficSecret(c.vers, hs.suite, clientTrafficSecret, clientWrite)
|
|
|
|
c.cipherSuite = hs.suite
|
|
c.resumptionSecret = hs.finishedHash.deriveSecret(masterSecret, resumptionLabel)
|
|
|
|
// TODO(davidben): Allow configuring the number of tickets sent for
|
|
// testing.
|
|
if !c.config.SessionTicketsDisabled && foundKEMode {
|
|
ticketCount := 2
|
|
for i := 0; i < ticketCount; i++ {
|
|
c.SendNewSessionTicket()
|
|
}
|
|
}
|
|
return nil
|
|
}
|
|
|
|
// processClientHello processes the ClientHello message from the client and
|
|
// decides whether we will perform session resumption.
|
|
func (hs *serverHandshakeState) processClientHello() (isResume bool, err error) {
|
|
config := hs.c.config
|
|
c := hs.c
|
|
|
|
hs.hello = &serverHelloMsg{
|
|
isDTLS: c.isDTLS,
|
|
vers: versionToWire(c.vers, c.isDTLS),
|
|
versOverride: config.Bugs.SendServerHelloVersion,
|
|
compressionMethod: compressionNone,
|
|
}
|
|
|
|
hs.hello.random = make([]byte, 32)
|
|
_, err = io.ReadFull(config.rand(), hs.hello.random)
|
|
if err != nil {
|
|
c.sendAlert(alertInternalError)
|
|
return false, err
|
|
}
|
|
// Signal downgrades in the server random, per draft-ietf-tls-tls13-16,
|
|
// section 4.1.3.
|
|
if c.vers <= VersionTLS12 && config.maxVersion(c.isDTLS) >= VersionTLS13 {
|
|
copy(hs.hello.random[len(hs.hello.random)-8:], downgradeTLS13)
|
|
}
|
|
if c.vers <= VersionTLS11 && config.maxVersion(c.isDTLS) == VersionTLS12 {
|
|
copy(hs.hello.random[len(hs.hello.random)-8:], downgradeTLS12)
|
|
}
|
|
|
|
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")
|
|
}
|
|
|
|
if err := hs.processClientExtensions(&hs.hello.extensions); err != nil {
|
|
return false, err
|
|
}
|
|
|
|
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
|
|
|
|
_, hs.ecdsaOk = hs.cert.PrivateKey.(*ecdsa.PrivateKey)
|
|
|
|
// For test purposes, check that the peer never offers a session when
|
|
// renegotiating.
|
|
if c.cipherSuite != nil && len(hs.clientHello.sessionId) > 0 && c.config.Bugs.FailIfResumeOnRenego {
|
|
return false, errors.New("tls: offered resumption on renegotiation")
|
|
}
|
|
|
|
if c.config.Bugs.FailIfSessionOffered && (len(hs.clientHello.sessionTicket) > 0 || len(hs.clientHello.sessionId) > 0) {
|
|
return false, errors.New("tls: client offered a session ticket or ID")
|
|
}
|
|
|
|
if hs.checkForResumption() {
|
|
return true, nil
|
|
}
|
|
|
|
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
|
|
}
|
|
|
|
// processClientExtensions processes all ClientHello extensions not directly
|
|
// related to cipher suite negotiation and writes responses in serverExtensions.
|
|
func (hs *serverHandshakeState) processClientExtensions(serverExtensions *serverExtensions) error {
|
|
config := hs.c.config
|
|
c := hs.c
|
|
|
|
if c.vers < VersionTLS13 || config.Bugs.NegotiateRenegotiationInfoAtAllVersions {
|
|
if !bytes.Equal(c.clientVerify, hs.clientHello.secureRenegotiation) {
|
|
c.sendAlert(alertHandshakeFailure)
|
|
return errors.New("tls: renegotiation mismatch")
|
|
}
|
|
|
|
if len(c.clientVerify) > 0 && !c.config.Bugs.EmptyRenegotiationInfo {
|
|
serverExtensions.secureRenegotiation = append(serverExtensions.secureRenegotiation, c.clientVerify...)
|
|
serverExtensions.secureRenegotiation = append(serverExtensions.secureRenegotiation, c.serverVerify...)
|
|
if c.config.Bugs.BadRenegotiationInfo {
|
|
serverExtensions.secureRenegotiation[0] ^= 0x80
|
|
}
|
|
} else {
|
|
serverExtensions.secureRenegotiation = hs.clientHello.secureRenegotiation
|
|
}
|
|
|
|
if c.noRenegotiationInfo() {
|
|
serverExtensions.secureRenegotiation = nil
|
|
}
|
|
}
|
|
|
|
serverExtensions.duplicateExtension = c.config.Bugs.DuplicateExtension
|
|
|
|
if len(hs.clientHello.serverName) > 0 {
|
|
c.serverName = hs.clientHello.serverName
|
|
}
|
|
if len(config.Certificates) == 0 {
|
|
c.sendAlert(alertInternalError)
|
|
return 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 errors.New("tls: unexpected server name")
|
|
}
|
|
|
|
if len(hs.clientHello.alpnProtocols) > 0 {
|
|
if proto := c.config.Bugs.ALPNProtocol; proto != nil {
|
|
serverExtensions.alpnProtocol = *proto
|
|
serverExtensions.alpnProtocolEmpty = len(*proto) == 0
|
|
c.clientProtocol = *proto
|
|
c.usedALPN = true
|
|
} else if selectedProto, fallback := mutualProtocol(hs.clientHello.alpnProtocols, c.config.NextProtos); !fallback {
|
|
serverExtensions.alpnProtocol = selectedProto
|
|
c.clientProtocol = selectedProto
|
|
c.usedALPN = true
|
|
}
|
|
}
|
|
|
|
if len(c.config.Bugs.SendALPN) > 0 {
|
|
serverExtensions.alpnProtocol = c.config.Bugs.SendALPN
|
|
}
|
|
|
|
if c.vers < VersionTLS13 || config.Bugs.NegotiateNPNAtAllVersions {
|
|
if len(hs.clientHello.alpnProtocols) == 0 || c.config.Bugs.NegotiateALPNAndNPN {
|
|
// 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 {
|
|
serverExtensions.nextProtoNeg = true
|
|
serverExtensions.nextProtos = config.NextProtos
|
|
serverExtensions.npnAfterAlpn = config.Bugs.SwapNPNAndALPN
|
|
}
|
|
}
|
|
}
|
|
|
|
if c.vers < VersionTLS13 || config.Bugs.NegotiateEMSAtAllVersions {
|
|
disableEMS := config.Bugs.NoExtendedMasterSecret
|
|
if c.cipherSuite != nil {
|
|
disableEMS = config.Bugs.NoExtendedMasterSecretOnRenegotiation
|
|
}
|
|
serverExtensions.extendedMasterSecret = c.vers >= VersionTLS10 && hs.clientHello.extendedMasterSecret && !disableEMS
|
|
}
|
|
|
|
if hs.clientHello.channelIDSupported && config.RequestChannelID {
|
|
serverExtensions.channelIDRequested = true
|
|
}
|
|
|
|
if hs.clientHello.srtpProtectionProfiles != nil {
|
|
SRTPLoop:
|
|
for _, p1 := range c.config.SRTPProtectionProfiles {
|
|
for _, p2 := range hs.clientHello.srtpProtectionProfiles {
|
|
if p1 == p2 {
|
|
serverExtensions.srtpProtectionProfile = p1
|
|
c.srtpProtectionProfile = p1
|
|
break SRTPLoop
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
if c.config.Bugs.SendSRTPProtectionProfile != 0 {
|
|
serverExtensions.srtpProtectionProfile = c.config.Bugs.SendSRTPProtectionProfile
|
|
}
|
|
|
|
if expected := c.config.Bugs.ExpectedCustomExtension; expected != nil {
|
|
if hs.clientHello.customExtension != *expected {
|
|
return fmt.Errorf("tls: bad custom extension contents %q", hs.clientHello.customExtension)
|
|
}
|
|
}
|
|
serverExtensions.customExtension = config.Bugs.CustomExtension
|
|
|
|
if c.config.Bugs.AdvertiseTicketExtension {
|
|
serverExtensions.ticketSupported = true
|
|
}
|
|
|
|
if !hs.clientHello.hasGREASEExtension && config.Bugs.ExpectGREASE {
|
|
return errors.New("tls: no GREASE extension found")
|
|
}
|
|
|
|
return nil
|
|
}
|
|
|
|
// checkForResumption returns true if we should perform resumption on this connection.
|
|
func (hs *serverHandshakeState) checkForResumption() bool {
|
|
c := hs.c
|
|
|
|
ticket := hs.clientHello.sessionTicket
|
|
if len(ticket) == 0 && len(hs.clientHello.pskIdentities) > 0 && c.config.Bugs.AcceptAnySession {
|
|
ticket = hs.clientHello.pskIdentities[0].ticket
|
|
}
|
|
if len(ticket) > 0 {
|
|
if c.config.SessionTicketsDisabled {
|
|
return false
|
|
}
|
|
|
|
var ok bool
|
|
if hs.sessionState, ok = c.decryptTicket(ticket); !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
|
|
}
|
|
}
|
|
|
|
if c.config.Bugs.AcceptAnySession {
|
|
// Replace the cipher suite with one known to work, to test
|
|
// cross-version resumption attempts.
|
|
hs.sessionState.cipherSuite = TLS_RSA_WITH_AES_128_CBC_SHA
|
|
} else {
|
|
// Never resume a session for a different SSL version.
|
|
if 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(), c.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
|
|
if c.config.Bugs.SendCipherSuite != 0 {
|
|
hs.hello.cipherSuite = c.config.Bugs.SendCipherSuite
|
|
}
|
|
// 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.extensions.ticketSupported = c.config.Bugs.RenewTicketOnResume
|
|
|
|
if c.config.Bugs.SendSCTListOnResume != nil {
|
|
hs.hello.extensions.sctList = c.config.Bugs.SendSCTListOnResume
|
|
}
|
|
|
|
if c.config.Bugs.SendOCSPResponseOnResume != nil {
|
|
// There is no way, syntactically, to send an OCSP response on a
|
|
// resumption handshake.
|
|
hs.hello.extensions.ocspStapling = true
|
|
}
|
|
|
|
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.extensions.ocspStapling = true
|
|
}
|
|
|
|
if hs.clientHello.sctListSupported && len(hs.cert.SignedCertificateTimestampList) > 0 {
|
|
hs.hello.extensions.sctList = hs.cert.SignedCertificateTimestampList
|
|
}
|
|
|
|
hs.hello.extensions.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.extensions.extendedMasterSecret
|
|
|
|
// Generate a session ID if we're to save the session.
|
|
if !hs.hello.extensions.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())
|
|
|
|
if config.Bugs.SendSNIWarningAlert {
|
|
c.SendAlert(alertLevelWarning, alertUnrecognizedName)
|
|
}
|
|
|
|
c.writeRecord(recordTypeHandshake, hs.hello.marshal())
|
|
|
|
if !isPSK {
|
|
certMsg := new(certificateMsg)
|
|
if !config.Bugs.EmptyCertificateList {
|
|
for _, certData := range hs.cert.Certificate {
|
|
certMsg.certificates = append(certMsg.certificates, certificateEntry{
|
|
data: certData,
|
|
})
|
|
}
|
|
}
|
|
if !config.Bugs.UnauthenticatedECDH {
|
|
certMsgBytes := certMsg.marshal()
|
|
hs.writeServerHash(certMsgBytes)
|
|
c.writeRecord(recordTypeHandshake, certMsgBytes)
|
|
}
|
|
}
|
|
|
|
if hs.hello.extensions.ocspStapling && !c.config.Bugs.SkipCertificateStatus {
|
|
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 ecdhe, ok := keyAgreement.(*ecdheKeyAgreement); ok {
|
|
c.curveID = ecdhe.curveID
|
|
}
|
|
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.hasSignatureAlgorithm = true
|
|
if !config.Bugs.NoSignatureAlgorithms {
|
|
certReq.signatureAlgorithms = config.verifySignatureAlgorithms()
|
|
}
|
|
}
|
|
|
|
// 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())
|
|
c.flushHandshake()
|
|
|
|
var pub crypto.PublicKey // public key for client auth, if any
|
|
|
|
if err := c.simulatePacketLoss(nil); err != nil {
|
|
return err
|
|
}
|
|
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
|
|
var certificates [][]byte
|
|
if certMsg, ok = msg.(*certificateMsg); ok {
|
|
if c.vers == VersionSSL30 && len(certMsg.certificates) == 0 {
|
|
return errors.New("tls: empty certificate message in SSL 3.0")
|
|
}
|
|
|
|
hs.writeClientHash(certMsg.marshal())
|
|
for _, cert := range certMsg.certificates {
|
|
certificates = append(certificates, cert.data)
|
|
}
|
|
} else if c.vers != VersionSSL30 {
|
|
// In TLS, the Certificate message is required. In SSL
|
|
// 3.0, the peer skips it when sending no certificates.
|
|
c.sendAlert(alertUnexpectedMessage)
|
|
return unexpectedMessageError(certMsg, msg)
|
|
}
|
|
|
|
if len(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(certificates)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
|
|
if ok {
|
|
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 sigAlg signatureAlgorithm
|
|
if certVerify.hasSignatureAlgorithm {
|
|
sigAlg = certVerify.signatureAlgorithm
|
|
c.peerSignatureAlgorithm = sigAlg
|
|
}
|
|
|
|
if c.vers > VersionSSL30 {
|
|
err = verifyMessage(c.vers, pub, c.config, sigAlg, hs.finishedHash.buffer, certVerify.signature)
|
|
} else {
|
|
// SSL 3.0's client certificate construction is
|
|
// incompatible with signatureAlgorithm.
|
|
rsaPub, ok := pub.(*rsa.PublicKey)
|
|
if !ok {
|
|
err = errors.New("unsupported key type for client certificate")
|
|
} else {
|
|
digest := hs.finishedHash.hashForClientCertificateSSL3(hs.masterSecret)
|
|
err = rsa.VerifyPKCS1v15(rsaPub, crypto.MD5SHA1, 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(c.vers))
|
|
|
|
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(c.vers, clientKey, clientIV)
|
|
serverCipher = hs.suite.aead(c.vers, serverKey, serverIV)
|
|
}
|
|
|
|
c.in.prepareCipherSpec(c.vers, clientCipher, clientHash)
|
|
c.out.prepareCipherSpec(c.vers, serverCipher, serverHash)
|
|
|
|
return nil
|
|
}
|
|
|
|
func (hs *serverHandshakeState) readFinished(out []byte, isResume bool) error {
|
|
c := hs.c
|
|
|
|
c.readRecord(recordTypeChangeCipherSpec)
|
|
if err := c.in.error(); err != nil {
|
|
return err
|
|
}
|
|
|
|
if hs.hello.extensions.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.extensions.channelIDRequested {
|
|
msg, err := c.readHandshake()
|
|
if err != nil {
|
|
return err
|
|
}
|
|
channelIDMsg, ok := msg.(*channelIDMsg)
|
|
if !ok {
|
|
c.sendAlert(alertUnexpectedMessage)
|
|
return unexpectedMessageError(channelIDMsg, msg)
|
|
}
|
|
var resumeHash []byte
|
|
if isResume {
|
|
resumeHash = hs.sessionState.handshakeHash
|
|
}
|
|
channelID, err := verifyChannelIDMessage(channelIDMsg, hs.finishedHash.hashForChannelID(resumeHash))
|
|
if err != nil {
|
|
return err
|
|
}
|
|
c.channelID = channelID
|
|
|
|
hs.writeClientHash(channelIDMsg.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...)
|
|
copy(out, 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.Sum(),
|
|
}
|
|
|
|
if !hs.hello.extensions.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)
|
|
|
|
if !c.config.Bugs.SendEmptySessionTicket {
|
|
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(out []byte) error {
|
|
c := hs.c
|
|
|
|
finished := new(finishedMsg)
|
|
finished.verifyData = hs.finishedHash.serverSum(hs.masterSecret)
|
|
copy(out, finished.verifyData)
|
|
if c.config.Bugs.BadFinished {
|
|
finished.verifyData[0]++
|
|
}
|
|
c.serverVerify = append(c.serverVerify[:0], finished.verifyData...)
|
|
hs.finishedBytes = finished.marshal()
|
|
hs.writeServerHash(hs.finishedBytes)
|
|
postCCSBytes := hs.finishedBytes
|
|
|
|
if c.config.Bugs.FragmentAcrossChangeCipherSpec {
|
|
c.writeRecord(recordTypeHandshake, postCCSBytes[:5])
|
|
postCCSBytes = postCCSBytes[5:]
|
|
} else if c.config.Bugs.SendUnencryptedFinished {
|
|
c.writeRecord(recordTypeHandshake, postCCSBytes)
|
|
postCCSBytes = nil
|
|
}
|
|
c.flushHandshake()
|
|
|
|
if !c.config.Bugs.SkipChangeCipherSpec {
|
|
ccs := []byte{1}
|
|
if c.config.Bugs.BadChangeCipherSpec != nil {
|
|
ccs = c.config.Bugs.BadChangeCipherSpec
|
|
}
|
|
c.writeRecord(recordTypeChangeCipherSpec, ccs)
|
|
}
|
|
|
|
if c.config.Bugs.AppDataAfterChangeCipherSpec != nil {
|
|
c.writeRecord(recordTypeApplicationData, c.config.Bugs.AppDataAfterChangeCipherSpec)
|
|
}
|
|
if c.config.Bugs.AlertAfterChangeCipherSpec != 0 {
|
|
c.sendAlert(c.config.Bugs.AlertAfterChangeCipherSpec)
|
|
return errors.New("tls: simulating post-CCS alert")
|
|
}
|
|
|
|
if !c.config.Bugs.SkipFinished && len(postCCSBytes) > 0 {
|
|
c.writeRecord(recordTypeHandshake, postCCSBytes)
|
|
if c.config.Bugs.SendExtraFinished {
|
|
c.writeRecord(recordTypeHandshake, finished.marshal())
|
|
}
|
|
|
|
if !c.config.Bugs.PackHelloRequestWithFinished {
|
|
// Defer flushing until renegotiation.
|
|
c.flushHandshake()
|
|
}
|
|
}
|
|
|
|
c.cipherSuite = hs.suite
|
|
|
|
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 verifyChannelIDMessage(channelIDMsg *channelIDMsg, channelIDHash []byte) (*ecdsa.PublicKey, error) {
|
|
x := new(big.Int).SetBytes(channelIDMsg.channelID[0:32])
|
|
y := new(big.Int).SetBytes(channelIDMsg.channelID[32:64])
|
|
r := new(big.Int).SetBytes(channelIDMsg.channelID[64:96])
|
|
s := new(big.Int).SetBytes(channelIDMsg.channelID[96:128])
|
|
if !elliptic.P256().IsOnCurve(x, y) {
|
|
return nil, errors.New("tls: invalid channel ID public key")
|
|
}
|
|
channelID := &ecdsa.PublicKey{elliptic.P256(), x, y}
|
|
if !ecdsa.Verify(channelID, channelIDHash, r, s) {
|
|
return nil, errors.New("tls: invalid channel ID signature")
|
|
}
|
|
return channelID, 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 version >= VersionTLS13 || candidate.flags&suiteTLS13 != 0 {
|
|
if version < VersionTLS13 || candidate.flags&suiteTLS13 == 0 {
|
|
continue
|
|
}
|
|
return candidate
|
|
}
|
|
if (candidate.flags&suiteECDHE != 0) && !ellipticOk {
|
|
continue
|
|
}
|
|
if (candidate.flags&suiteECDSA != 0) != ecdsaOk {
|
|
continue
|
|
}
|
|
if version < VersionTLS12 && candidate.flags&suiteTLS12 != 0 {
|
|
continue
|
|
}
|
|
if c.isDTLS && candidate.flags&suiteNoDTLS != 0 {
|
|
continue
|
|
}
|
|
return candidate
|
|
}
|
|
}
|
|
|
|
return nil
|
|
}
|
|
|
|
func isTLS12Cipher(id uint16) bool {
|
|
for _, cipher := range cipherSuites {
|
|
if cipher.id != id {
|
|
continue
|
|
}
|
|
return cipher.flags&suiteTLS12 != 0
|
|
}
|
|
// Unknown cipher.
|
|
return false
|
|
}
|
|
|
|
func isGREASEValue(val uint16) bool {
|
|
return val&0x0f0f == 0x0a0a && val&0xff == val>>8
|
|
}
|
|
|
|
func verifyPSKBinder(clientHello *clientHelloMsg, sessionState *sessionState, binderToVerify, transcript []byte) error {
|
|
binderLen := 2
|
|
for _, binder := range clientHello.pskBinders {
|
|
binderLen += 1 + len(binder)
|
|
}
|
|
|
|
truncatedHello := clientHello.marshal()
|
|
truncatedHello = truncatedHello[:len(truncatedHello)-binderLen]
|
|
pskCipherSuite := cipherSuiteFromID(sessionState.cipherSuite)
|
|
if pskCipherSuite == nil {
|
|
return errors.New("tls: Unknown cipher suite for PSK in session")
|
|
}
|
|
|
|
binder := computePSKBinder(sessionState.masterSecret, resumptionPSKBinderLabel, pskCipherSuite, transcript, truncatedHello)
|
|
if !bytes.Equal(binder, binderToVerify) {
|
|
return errors.New("tls: PSK binder does not verify")
|
|
}
|
|
|
|
return nil
|
|
}
|