// Copyright 2009 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package tls
import (
"crypto"
"crypto/ecdsa"
"crypto/ed25519"
"crypto/rsa"
"crypto/subtle"
"crypto/x509"
"errors"
"fmt"
"io"
"sync/atomic"
"time"
)
// serverHandshakeState contains details of a server handshake in progress.
// It's discarded once the handshake has completed.
type serverHandshakeState struct {
c *Conn
clientHello *clientHelloMsg
hello *serverHelloMsg
suite *cipherSuite
ecdheOk bool
ecSignOk bool
rsaDecryptOk bool
rsaSignOk bool
sessionState *sessionState
finishedHash finishedHash
masterSecret []byte
cert *Certificate
}
// serverHandshake performs a TLS handshake as a server.
func (c *Conn) serverHandshake() error {
clientHello, err := c.readClientHello()
if err != nil {
return err
}
if c.vers == VersionTLS13 {
hs := serverHandshakeStateTLS13{
c: c,
clientHello: clientHello,
}
return hs.handshake()
}
hs := serverHandshakeState{
c: c,
clientHello: clientHello,
}
return hs.handshake()
}
func (hs *serverHandshakeState) handshake() error {
c := hs.c
if err := hs.processClientHello(); err != nil {
return err
}
// For an overview of TLS handshaking, see RFC 5246, Section 7.3.
c.buffering = true
if hs.checkForResumption() {
// The client has included a session ticket and so we do an abbreviated handshake.
c.didResume = true
if err := hs.doResumeHandshake(); err != nil {
return err
}
if err := hs.establishKeys(); err != nil {
return err
}
if err := hs.sendSessionTicket(); err != nil {
return err
}
if err := hs.sendFinished(c.serverFinished[:]); err != nil {
return err
}
if _, err := c.flush(); err != nil {
return err
}
c.clientFinishedIsFirst = false
if err := hs.readFinished(nil); err != nil {
return err
}
} else {
// The client didn't include a session ticket, or it wasn't
// valid so we do a full handshake.
if err := hs.pickCipherSuite(); err != nil {
return err
}
if err := hs.doFullHandshake(); err != nil {
return err
}
if err := hs.establishKeys(); err != nil {
return err
}
if err := hs.readFinished(c.clientFinished[:]); err != nil {
return err
}
c.clientFinishedIsFirst = true
c.buffering = true
if err := hs.sendSessionTicket(); err != nil {
return err
}
if err := hs.sendFinished(nil); err != nil {
return err
}
if _, err := c.flush(); err != nil {
return err
}
}
c.ekm = ekmFromMasterSecret(c.vers, hs.suite, hs.masterSecret, hs.clientHello.random, hs.hello.random)
atomic.StoreUint32(&c.handshakeStatus, 1)
return nil
}
// readClientHello reads a ClientHello message and selects the protocol version.
func (c *Conn) readClientHello() (*clientHelloMsg, error) {
msg, err := c.readHandshake()
if err != nil {
return nil, err
}
clientHello, ok := msg.(*clientHelloMsg)
if !ok {
c.sendAlert(alertUnexpectedMessage)
return nil, unexpectedMessageError(clientHello, msg)
}
var configForClient *Config
originalConfig := c.config
if c.config.GetConfigForClient != nil {
chi := clientHelloInfo(c, clientHello)
if configForClient, err = c.config.GetConfigForClient(chi); err != nil {
c.sendAlert(alertInternalError)
return nil, err
} else if configForClient != nil