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// 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-Go file.
package reality
import (
"context"
"crypto"
"crypto/ecdsa"
"crypto/ed25519"
"crypto/rsa"
"crypto/subtle"
"crypto/x509"
"errors"
"fmt"
"hash"
"io"
"time"
)
// serverHandshakeState contains details of a server handshake in progress.
// It's discarded once the handshake has completed.
type serverHandshakeState struct {
c *Conn
ctx context.Context
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(ctx context.Context) error {
clientHello, err := c.readClientHello(ctx)
if err != nil {
return err
}
if c.vers == VersionTLS13 {
hs := serverHandshakeStateTLS13{
c: c,
ctx: ctx,
clientHello: clientHello,
}
return hs.handshake()
}
hs := serverHandshakeState{
c: c,
ctx: ctx,
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 err := hs.checkForResumption(); err != nil {
return err
}
if hs.sessionState != nil {
// The client has included a session ticket and so we do an abbreviated handshake.
if err := hs.doResumeHandshake(); err != nil {
return err
}
if err := hs.establishKeys(); err != nil {
return err
}
if 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)
c.isHandshakeComplete.Store(true)
return nil
}
// readClientHello reads a ClientHello message and selects the protocol version.
func (c *Conn) readClientHello(ctx context.Context) (*clientHelloMsg, error) {
// clientHelloMsg is included in the transcript, but we haven't initialized
// it yet. The respective handshake functions will record it themselves.
msg, err := c.readHandshake(nil)
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(ctx, c, clientHello)
if configForClient, err = c.config.GetConfigForClient(chi); err != nil {
c.sendAlert(alertInternalError)
return nil, err
} else if configForClient != nil {
c.config = configForClient
}
}
c.ticketKeys = originalConfig.ticketKeys(configForClient)
clientVersions := clientHello.supportedVersions
if len(clientHello.supportedVersions) == 0 {
clientVersions = supportedVersionsFromMax(clientHello.vers)
}
c.vers, ok = c.config.mutualVersion(roleServer, clientVersions)
if !ok {
c.sendAlert(alertProtocolVersion)
return nil, fmt.Errorf("tls: client offered only unsupported versions: %x", clientVersions)
}
c.haveVers = true
c.in.version = c.vers
c.out.version = c.vers
return clientHello, nil
}
func (hs *serverHandshakeState) processClientHello() error {
c := hs.c
hs.hello = new(serverHelloMsg)
hs.hello.vers = c.vers
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 errors.New("tls: client does not support uncompressed connections")
}
hs.hello.random = make([]byte, 32)
serverRandom := hs.hello.random
// Downgrade protection canaries. See RFC 8446, Section 4.1.3.
maxVers := c.config.maxSupportedVersion(roleServer)
if maxVers >= VersionTLS12 && c.vers < maxVers || testingOnlyForceDowngradeCanary {
if c.vers == VersionTLS12 {
copy(serverRandom[24:], downgradeCanaryTLS12)
} else {
copy(serverRandom[24:], downgradeCanaryTLS11)
}
serverRandom = serverRandom[:24]
}
_, err := io.ReadFull(c.config.rand(), serverRandom)
if err != nil {
c.sendAlert(alertInternalError)
return err
}
if len(hs.clientHello.secureRenegotiation) != 0 {
c.sendAlert(alertHandshakeFailure)
return errors.New("tls: initial handshake had non-empty renegotiation extension")
}
hs.hello.extendedMasterSecret = hs.clientHello.extendedMasterSecret
hs.hello.secureRenegotiationSupported = hs.clientHello.secureRenegotiationSupported
hs.hello.compressionMethod = compressionNone
if len(hs.clientHello.serverName) > 0 {
c.serverName = hs.clientHello.serverName
}
selectedProto, err := negotiateALPN(c.config.NextProtos, hs.clientHello.alpnProtocols, false)
if err != nil {
c.sendAlert(alertNoApplicationProtocol)
return err
}
hs.hello.alpnProtocol = selectedProto
c.clientProtocol = selectedProto
hs.cert, err = c.config.getCertificate(clientHelloInfo(hs.ctx, c, hs.clientHello))
if err != nil {
if err == errNoCertificates {
c.sendAlert(alertUnrecognizedName)
} else {
c.sendAlert(alertInternalError)
}
return err
}
if hs.clientHello.scts {
hs.hello.scts = hs.cert.SignedCertificateTimestamps
}
hs.ecdheOk = supportsECDHE(c.config, hs.clientHello.supportedCurves, hs.clientHello.supportedPoints)
if hs.ecdheOk && len(hs.clientHello.supportedPoints) > 0 {
// Although omitting the ec_point_formats extension is permitted, some
// old OpenSSL version will refuse to handshake if not present.
//
// Per RFC 4492, section 5.1.2, implementations MUST support the
// uncompressed point format. See golang.org/issue/31943.
hs.hello.supportedPoints = []uint8{pointFormatUncompressed}
}
if priv, ok := hs.cert.PrivateKey.(crypto.Signer); ok {
switch priv.Public().(type) {
case *ecdsa.PublicKey:
hs.ecSignOk = true
case ed25519.PublicKey:
hs.ecSignOk = true
case *rsa.PublicKey:
hs.rsaSignOk = true
default:
c.sendAlert(alertInternalError)
return fmt.Errorf("tls: unsupported signing key type (%T)", priv.Public())
}
}
if priv, ok := hs.cert.PrivateKey.(crypto.Decrypter); ok {
switch priv.Public().(type) {
case *rsa.PublicKey:
hs.rsaDecryptOk = true
default:
c.sendAlert(alertInternalError)
return fmt.Errorf("tls: unsupported decryption key type (%T)", priv.Public())
}
}
return nil
}
// negotiateALPN picks a shared ALPN protocol that both sides support in server
// preference order. If ALPN is not configured or the peer doesn't support it,
// it returns "" and no error.
func negotiateALPN(serverProtos, clientProtos []string, quic bool) (string, error) {
if len(serverProtos) == 0 || len(clientProtos) == 0 {
if quic && len(serverProtos) != 0 {
// RFC 9001, Section 8.1
return "", fmt.Errorf("tls: client did not request an application protocol")
}
return "", nil
}
var http11fallback bool
for _, s := range serverProtos {
for _, c := range clientProtos {
if s == c {
return s, nil
}
if s == "h2" && c == "http/1.1" {
http11fallback = true
}
}
}
// As a special case, let http/1.1 clients connect to h2 servers as if they
// didn't support ALPN. We used not to enforce protocol overlap, so over
// time a number of HTTP servers were configured with only "h2", but
// expected to accept connections from "http/1.1" clients. See Issue 46310.
if http11fallback {
return "", nil
}
return "", fmt.Errorf("tls: client requested unsupported application protocols (%s)", clientProtos)
}
// supportsECDHE returns whether ECDHE key exchanges can be used with this
// pre-TLS 1.3 client.
func supportsECDHE(c *Config, supportedCurves []CurveID, supportedPoints []uint8) bool {
supportsCurve := false
for _, curve := range supportedCurves {
if c.supportsCurve(curve) {
supportsCurve = true
break
}
}
supportsPointFormat := false
for _, pointFormat := range supportedPoints {
if pointFormat == pointFormatUncompressed {
supportsPointFormat = true
break
}
}
// Per RFC 8422, Section 5.1.2, if the Supported Point Formats extension is
// missing, uncompressed points are supported. If supportedPoints is empty,
// the extension must be missing, as an empty extension body is rejected by
// the parser. See https://go.dev/issue/49126.
if len(supportedPoints) == 0 {
supportsPointFormat = true
}
return supportsCurve && supportsPointFormat
}
func (hs *serverHandshakeState) pickCipherSuite() error {
c := hs.c
preferenceOrder := cipherSuitesPreferenceOrder
if !hasAESGCMHardwareSupport || !aesgcmPreferred(hs.clientHello.cipherSuites) {
preferenceOrder = cipherSuitesPreferenceOrderNoAES
}
configCipherSuites := c.config.cipherSuites()
preferenceList := make([]uint16, 0, len(configCipherSuites))
for _, suiteID := range preferenceOrder {
for _, id := range configCipherSuites {
if id == suiteID {
preferenceList = append(preferenceList, id)
break
}
}
}
hs.suite = selectCipherSuite(preferenceList, hs.clientHello.cipherSuites, hs.cipherSuiteOk)
if hs.suite == nil {
c.sendAlert(alertHandshakeFailure)
return errors.New("tls: no cipher suite supported by both client and server")
}
c.cipherSuite = hs.suite.id
for _, id := range hs.clientHello.cipherSuites {
if id == TLS_FALLBACK_SCSV {
// The client is doing a fallback connection. See RFC 7507.
if hs.clientHello.vers < c.config.maxSupportedVersion(roleServer) {
c.sendAlert(alertInappropriateFallback)
return errors.New("tls: client using inappropriate protocol fallback")
}
break
}
}
return nil
}
func (hs *serverHandshakeState) cipherSuiteOk(c *cipherSuite) bool {
if c.flags&suiteECDHE != 0 {
if !hs.ecdheOk {
return false
}
if c.flags&suiteECSign != 0 {
if !hs.ecSignOk {
return false
}
} else if !hs.rsaSignOk {
return false
}
} else if !hs.rsaDecryptOk {
return false
}
if hs.c.vers < VersionTLS12 && c.flags&suiteTLS12 != 0 {
return false
}
return true
}
// checkForResumption reports whether we should perform resumption on this connection.
func (hs *serverHandshakeState) checkForResumption() error {
c := hs.c
if c.config.SessionTicketsDisabled {
return nil
}
var sessionState *SessionState
if c.config.UnwrapSession != nil {
ss, err := c.config.UnwrapSession(hs.clientHello.sessionTicket, c.connectionStateLocked())
if err != nil {
return err
}
if ss == nil {
return nil
}
sessionState = ss
} else {
plaintext := c.config.decryptTicket(hs.clientHello.sessionTicket, c.ticketKeys)
if plaintext == nil {
return nil
}
ss, err := ParseSessionState(plaintext)
if err != nil {
return nil
}
sessionState = ss
}
// TLS 1.2 tickets don't natively have a lifetime, but we want to avoid
// re-wrapping the same master secret in different tickets over and over for
// too long, weakening forward secrecy.
createdAt := time.Unix(int64(sessionState.createdAt), 0)
if c.config.time().Sub(createdAt) > maxSessionTicketLifetime {
return nil
}
// Never resume a session for a different TLS version.
if c.vers != sessionState.version {
return nil
}
cipherSuiteOk := false
// Check that the client is still offering the ciphersuite in the session.
for _, id := range hs.clientHello.cipherSuites {
if id == sessionState.cipherSuite {
cipherSuiteOk = true
break
}
}
if !cipherSuiteOk {
return nil
}
// Check that we also support the ciphersuite from the session.
suite := selectCipherSuite([]uint16{sessionState.cipherSuite},
c.config.cipherSuites(), hs.cipherSuiteOk)
if suite == nil {
return nil
}
sessionHasClientCerts := len(sessionState.peerCertificates) != 0
needClientCerts := requiresClientCert(c.config.ClientAuth)
if needClientCerts && !sessionHasClientCerts {
return nil
}
if sessionHasClientCerts && c.config.ClientAuth == NoClientCert {
return nil
}
if sessionHasClientCerts && c.config.time().After(sessionState.peerCertificates[0].NotAfter) {
return nil
}
if sessionHasClientCerts && c.config.ClientAuth >= VerifyClientCertIfGiven &&
len(sessionState.verifiedChains) == 0 {
return nil
}
// RFC 7627, Section 5.3
if !sessionState.extMasterSecret && hs.clientHello.extendedMasterSecret {
return nil
}
if sessionState.extMasterSecret && !hs.clientHello.extendedMasterSecret {
// Aborting is somewhat harsh, but it's a MUST and it would indicate a
// weird downgrade in client capabilities.
return errors.New("tls: session supported extended_master_secret but client does not")
}
c.peerCertificates = sessionState.peerCertificates
c.ocspResponse = sessionState.ocspResponse
c.scts = sessionState.scts
c.verifiedChains = sessionState.verifiedChains
c.extMasterSecret = sessionState.extMasterSecret
hs.sessionState = sessionState
hs.suite = suite
c.didResume = true
return nil
}
func (hs *serverHandshakeState) doResumeHandshake() error {
c := hs.c
hs.hello.cipherSuite = hs.suite.id
c.cipherSuite = hs.suite.id
// We echo the client's session ID in the ServerHello to let it know
// that we're doing a resumption.
hs.hello.sessionId = hs.clientHello.sessionId
// We always send a new session ticket, even if it wraps the same master
// secret and it's potentially encrypted with the same key, to help the
// client avoid cross-connection tracking from a network observer.
hs.hello.ticketSupported = true
hs.finishedHash = newFinishedHash(c.vers, hs.suite)
hs.finishedHash.discardHandshakeBuffer()
if err := transcriptMsg(hs.clientHello, &hs.finishedHash); err != nil {
return err
}
if _, err := hs.c.writeHandshakeRecord(hs.hello, &hs.finishedHash); err != nil {
return err
}
if c.config.VerifyConnection != nil {
if err := c.config.VerifyConnection(c.connectionStateLocked()); err != nil {
c.sendAlert(alertBadCertificate)
return err
}
}
hs.masterSecret = hs.sessionState.secret
return nil
}
func (hs *serverHandshakeState) doFullHandshake() error {
c := hs.c
if hs.clientHello.ocspStapling && len(hs.cert.OCSPStaple) > 0 {
hs.hello.ocspStapling = true
}
hs.hello.ticketSupported = hs.clientHello.ticketSupported && !c.config.SessionTicketsDisabled
hs.hello.cipherSuite = hs.suite.id
hs.finishedHash = newFinishedHash(hs.c.vers, hs.suite)
if c.config.ClientAuth == NoClientCert {
// No need to keep a full record of the handshake if client
// certificates won't be used.
hs.finishedHash.discardHandshakeBuffer()
}
if err := transcriptMsg(hs.clientHello, &hs.finishedHash); err != nil {
return err
}
if _, err := hs.c.writeHandshakeRecord(hs.hello, &hs.finishedHash); err != nil {
return err
}
certMsg := new(certificateMsg)
certMsg.certificates = hs.cert.Certificate
if _, err := hs.c.writeHandshakeRecord(certMsg, &hs.finishedHash); err != nil {
return err
}
if hs.hello.ocspStapling {
certStatus := new(certificateStatusMsg)
certStatus.response = hs.cert.OCSPStaple
if _, err := hs.c.writeHandshakeRecord(certStatus, &hs.finishedHash); err != nil {
return err
}
}
keyAgreement := hs.suite.ka(c.vers)
skx, err := keyAgreement.generateServerKeyExchange(c.config, hs.cert, hs.clientHello, hs.hello)
if err != nil {
c.sendAlert(alertHandshakeFailure)
return err
}
if skx != nil {
if _, err := hs.c.writeHandshakeRecord(skx, &hs.finishedHash); err != nil {
return err
}
}
var certReq *certificateRequestMsg
if c.config.ClientAuth >= RequestClientCert {
// Request a client certificate
certReq = new(certificateRequestMsg)
certReq.certificateTypes = []byte{
byte(certTypeRSASign),
byte(certTypeECDSASign),
}
if c.vers >= VersionTLS12 {
certReq.hasSignatureAlgorithm = true
certReq.supportedSignatureAlgorithms = supportedSignatureAlgorithms()
}
// 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 c.config.ClientCAs != nil {
certReq.certificateAuthorities = c.config.ClientCAs.Subjects()
}
if _, err := hs.c.writeHandshakeRecord(certReq, &hs.finishedHash); err != nil {
return err
}
}
helloDone := new(serverHelloDoneMsg)
if _, err := hs.c.writeHandshakeRecord(helloDone, &hs.finishedHash); err != nil {
return err
}
if _, err := c.flush(); err != nil {
return err
}
var pub crypto.PublicKey // public key for client auth, if any
msg, err := c.readHandshake(&hs.finishedHash)
if err != nil {
return err
}
// If we requested a client certificate, then the client must send a
// certificate message, even if it's empty.
if c.config.ClientAuth >= RequestClientCert {
certMsg, ok := msg.(*certificateMsg)
if !ok {
c.sendAlert(alertUnexpectedMessage)
return unexpectedMessageError(certMsg, msg)
}
if err := c.processCertsFromClient(Certificate{
Certificate: certMsg.certificates,
}); err != nil {
return err
}
if len(certMsg.certificates) != 0 {
pub = c.peerCertificates[0].PublicKey
}
msg, err = c.readHandshake(&hs.finishedHash)
if err != nil {
return err
}
}
if c.config.VerifyConnection != nil {
if err := c.config.VerifyConnection(c.connectionStateLocked()); err != nil {
c.sendAlert(alertBadCertificate)
return err
}
}
// Get client key exchange
ckx, ok := msg.(*clientKeyExchangeMsg)
if !ok {
c.sendAlert(alertUnexpectedMessage)
return unexpectedMessageError(ckx, msg)
}
preMasterSecret, err := keyAgreement.processClientKeyExchange(c.config, hs.cert, ckx, c.vers)
if err != nil {
c.sendAlert(alertHandshakeFailure)
return err
}
if hs.hello.extendedMasterSecret {
c.extMasterSecret = true
hs.masterSecret = extMasterFromPreMasterSecret(c.vers, hs.suite, preMasterSecret,
hs.finishedHash.Sum())
} else {
hs.masterSecret = masterFromPreMasterSecret(c.vers, hs.suite, preMasterSecret,
hs.clientHello.random, hs.hello.random)
}
if err := c.config.writeKeyLog(keyLogLabelTLS12, hs.clientHello.random, hs.masterSecret); err != nil {
c.sendAlert(alertInternalError)
return err
}
// 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 {
// certificateVerifyMsg is included in the transcript, but not until
// after we verify the handshake signature, since the state before
// this message was sent is used.
msg, err = c.readHandshake(nil)
if err != nil {
return err
}
certVerify, ok := msg.(*certificateVerifyMsg)
if !ok {
c.sendAlert(alertUnexpectedMessage)
return unexpectedMessageError(certVerify, msg)
}
var sigType uint8
var sigHash crypto.Hash
if c.vers >= VersionTLS12 {
if !isSupportedSignatureAlgorithm(certVerify.signatureAlgorithm, certReq.supportedSignatureAlgorithms) {
c.sendAlert(alertIllegalParameter)
return errors.New("tls: client certificate used with invalid signature algorithm")
}
sigType, sigHash, err = typeAndHashFromSignatureScheme(certVerify.signatureAlgorithm)
if err != nil {
return c.sendAlert(alertInternalError)
}
} else {
sigType, sigHash, err = legacyTypeAndHashFromPublicKey(pub)
if err != nil {
c.sendAlert(alertIllegalParameter)
return err
}
}
signed := hs.finishedHash.hashForClientCertificate(sigType, sigHash)
if err := verifyHandshakeSignature(sigType, pub, sigHash, signed, certVerify.signature); err != nil {
c.sendAlert(alertDecryptError)
return errors.New("tls: invalid signature by the client certificate: " + err.Error())
}
if err := transcriptMsg(certVerify, &hs.finishedHash); err != nil {
return err
}
}
hs.finishedHash.discardHandshakeBuffer()
return nil
}
func (hs *serverHandshakeState) establishKeys() error {
c := hs.c
clientMAC, serverMAC, clientKey, serverKey, clientIV, serverIV :=
keysFromMasterSecret(c.vers, hs.suite, hs.masterSecret, hs.clientHello.random, hs.hello.random, hs.suite.macLen, hs.suite.keyLen, hs.suite.ivLen)
var clientCipher, serverCipher any
var clientHash, serverHash hash.Hash
if hs.suite.aead == nil {
clientCipher = hs.suite.cipher(clientKey, clientIV, true /* for reading */)
clientHash = hs.suite.mac(clientMAC)
serverCipher = hs.suite.cipher(serverKey, serverIV, false /* not for reading */)
serverHash = hs.suite.mac(serverMAC)
} else {
clientCipher = hs.suite.aead(clientKey, clientIV)
serverCipher = hs.suite.aead(serverKey, serverIV)
}
c.in.prepareCipherSpec(c.vers, clientCipher, clientHash)
c.out.prepareCipherSpec(c.vers, serverCipher, serverHash)
return nil
}
func (hs *serverHandshakeState) readFinished(out []byte) error {
c := hs.c
if err := c.readChangeCipherSpec(); err != nil {
return err
}
// finishedMsg is included in the transcript, but not until after we
// check the client version, since the state before this message was
// sent is used during verification.
msg, err := c.readHandshake(nil)
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")
}
if err := transcriptMsg(clientFinished, &hs.finishedHash); err != nil {
return err
}
copy(out, verify)
return nil
}
func (hs *serverHandshakeState) sendSessionTicket() error {
if !hs.hello.ticketSupported {
return nil
}
c := hs.c
m := new(newSessionTicketMsg)
state, err := c.sessionState()
if err != nil {
return err
}
state.secret = hs.masterSecret
if hs.sessionState != nil {
// If this is re-wrapping an old key, then keep
// the original time it was created.
state.createdAt = hs.sessionState.createdAt
}
if c.config.WrapSession != nil {
m.ticket, err = c.config.WrapSession(c.connectionStateLocked(), state)
if err != nil {
return err
}
} else {
stateBytes, err := state.Bytes()
if err != nil {
return err
}
m.ticket, err = c.config.encryptTicket(stateBytes, c.ticketKeys)
if err != nil {
return err
}
}
if _, err := hs.c.writeHandshakeRecord(m, &hs.finishedHash); err != nil {
return err
}
return nil
}
func (hs *serverHandshakeState) sendFinished(out []byte) error {
c := hs.c
if err := c.writeChangeCipherRecord(); err != nil {
return err
}
finished := new(finishedMsg)
finished.verifyData = hs.finishedHash.serverSum(hs.masterSecret)
if _, err := hs.c.writeHandshakeRecord(finished, &hs.finishedHash); err != nil {
return err
}
copy(out, finished.verifyData)
return nil
}
// processCertsFromClient takes a chain of client certificates either from a
// Certificates message and verifies them.
func (c *Conn) processCertsFromClient(certificate Certificate) error {
certificates := certificate.Certificate
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 errors.New("tls: failed to parse client certificate: " + err.Error())
}
if certs[i].PublicKeyAlgorithm == x509.RSA {
n := certs[i].PublicKey.(*rsa.PublicKey).N.BitLen()
if max, ok := checkKeySize(n); !ok {
c.sendAlert(alertBadCertificate)
return fmt.Errorf("tls: client sent certificate containing RSA key larger than %d bits", max)
}
}
}
if len(certs) == 0 && requiresClientCert(c.config.ClientAuth) {
if c.vers == VersionTLS13 {
c.sendAlert(alertCertificateRequired)
} else {
c.sendAlert(alertBadCertificate)
}
return errors.New("tls: client didn't provide a certificate")
}
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 {
var errCertificateInvalid x509.CertificateInvalidError
if errors.As(err, &x509.UnknownAuthorityError{}) {
c.sendAlert(alertUnknownCA)
} else if errors.As(err, &errCertificateInvalid) && errCertificateInvalid.Reason == x509.Expired {
c.sendAlert(alertCertificateExpired)
} else {
c.sendAlert(alertBadCertificate)
}
return &CertificateVerificationError{UnverifiedCertificates: certs, Err: err}
}
c.verifiedChains = chains
}
c.peerCertificates = certs
c.ocspResponse = certificate.OCSPStaple
c.scts = certificate.SignedCertificateTimestamps
if len(certs) > 0 {
switch certs[0].PublicKey.(type) {
case *ecdsa.PublicKey, *rsa.PublicKey, ed25519.PublicKey:
default:
c.sendAlert(alertUnsupportedCertificate)
return fmt.Errorf("tls: client certificate contains an unsupported public key of type %T", certs[0].PublicKey)
}
}
if c.config.VerifyPeerCertificate != nil {
if err := c.config.VerifyPeerCertificate(certificates, c.verifiedChains); err != nil {
c.sendAlert(alertBadCertificate)
return err
}
}
return nil
}
func clientHelloInfo(ctx context.Context, c *Conn, clientHello *clientHelloMsg) *ClientHelloInfo {
supportedVersions := clientHello.supportedVersions
if len(clientHello.supportedVersions) == 0 {
supportedVersions = supportedVersionsFromMax(clientHello.vers)
}
return &ClientHelloInfo{
CipherSuites: clientHello.cipherSuites,
ServerName: clientHello.serverName,
SupportedCurves: clientHello.supportedCurves,
SupportedPoints: clientHello.supportedPoints,
SignatureSchemes: clientHello.supportedSignatureAlgorithms,
SupportedProtos: clientHello.alpnProtocols,
SupportedVersions: supportedVersions,
Conn: c.conn,
config: c.config,
ctx: ctx,
}
}
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