release: merge back stable branch into default
release: merge back stable branch into default

File last commit:

r3370:ec7c0418 default
r3423:f8efae2b merge default
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2142 lines | 67.6 KiB | text/x-diff | DiffLexer
diff --git a/README.md b/README.md
--- a/README.md
+++ b/README.md
@@ -1,2 +1,2 @@
-hello initia
+hello initial
#############
diff --git a/example.go b/example.go
new file mode 100644
--- /dev/null
+++ b/example.go
@@ -0,0 +1,2130 @@
+// 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 runner
+
+import (
+ "bytes"
+ "crypto"
+ "crypto/ecdsa"
+ "crypto/elliptic"
+ "crypto/rsa"
+ "crypto/subtle"
+ "crypto/x509"
+ "errors"
+ "fmt"
+ "io"
+ "math/big"
+ "time"
+
+ "./ed25519"
+)
+
+// 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
+ ellipticOk bool
+ ecdsaOk bool
+ sessionState *sessionState
+ finishedHash finishedHash
+ masterSecret []byte
+ certsFromClient [][]byte
+ cert *Certificate
+ finishedBytes []byte
+}
+
+// serverHandshake performs a TLS handshake as a server.
+func (c *Conn) serverHandshake() error {
+ config := c.config
+
+ // If this is the first server handshake, we generate a random key to
+ // encrypt the tickets with.
+ config.serverInitOnce.Do(config.serverInit)
+
+ c.sendHandshakeSeq = 0
+ c.recvHandshakeSeq = 0
+
+ hs := serverHandshakeState{
+ c: c,
+ }
+ if err := hs.readClientHello(); err != nil {
+ return err
+ }
+
+ if c.vers >= VersionTLS13 {
+ if err := hs.doTLS13Handshake(); err != nil {
+ return err
+ }
+ } else {
+ isResume, err := hs.processClientHello()
+ if err != nil {
+ return err
+ }
+
+ // For an overview of TLS handshaking, see https://tools.ietf.org/html/rfc5246#section-7.3
+ if isResume {
+ // 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 c.config.Bugs.RenewTicketOnResume {
+ if err := hs.sendSessionTicket(); err != nil {
+ return err
+ }
+ }
+ if err := hs.sendFinished(c.firstFinished[:], isResume); err != nil {
+ return err
+ }
+ // Most retransmits are triggered by a timeout, but the final
+ // leg of the handshake is retransmited upon re-receiving a
+ // Finished.
+ if err := c.simulatePacketLoss(func() {
+ c.sendHandshakeSeq--
+ c.writeRecord(recordTypeHandshake, hs.finishedBytes)
+ c.flushHandshake()
+ }); err != nil {
+ return err
+ }
+ if err := hs.readFinished(nil, isResume); err != nil {
+ return err
+ }
+ c.didResume = true
+ } else {
+ // The client didn't include a session ticket, or it wasn't
+ // valid so we do a full handshake.
+ if err := hs.doFullHandshake(); err != nil {
+ return err
+ }
+ if err := hs.establishKeys(); err != nil {
+ return err
+ }
+ if err := hs.readFinished(c.firstFinished[:], isResume); err != nil {
+ return err
+ }
+ if c.config.Bugs.AlertBeforeFalseStartTest != 0 {
+ c.sendAlert(c.config.Bugs.AlertBeforeFalseStartTest)
+ }
+ if c.config.Bugs.ExpectFalseStart {
+ if err := c.readRecord(recordTypeApplicationData); err != nil {
+ return fmt.Errorf("tls: peer did not false start: %s", err)
+ }
+ }
+ if err := hs.sendSessionTicket(); err != nil {
+ return err
+ }
+ if err := hs.sendFinished(nil, isResume); err != nil {
+ return err
+ }
+ }
+
+ c.exporterSecret = hs.masterSecret
+ }
+ c.handshakeComplete = true
+ copy(c.clientRandom[:], hs.clientHello.random)
+ copy(c.serverRandom[:], hs.hello.random)
+
+ return nil
+}
+
+// readClientHello reads a ClientHello message from the client and determines
+// the protocol version.
+func (hs *serverHandshakeState) readClientHello() error {
+ config := hs.c.config
+ c := hs.c
+
+ if err := c.simulatePacketLoss(nil); err != nil {
+ return err
+ }
+ msg, err := c.readHandshake()
+ if err != nil {
+ return err
+ }
+ var ok bool
+ hs.clientHello, ok = msg.(*clientHelloMsg)
+ if !ok {
+ c.sendAlert(alertUnexpectedMessage)
+ return unexpectedMessageError(hs.clientHello, msg)
+ }
+ if size := config.Bugs.RequireClientHelloSize; size != 0 && len(hs.clientHello.raw) != size {
+ return fmt.Errorf("tls: ClientHello record size is %d, but expected %d", len(hs.clientHello.raw), size)
+ }
+
+ if c.isDTLS && !config.Bugs.SkipHelloVerifyRequest {
+ // Per RFC 6347, the version field in HelloVerifyRequest SHOULD
+ // be always DTLS 1.0
+ helloVerifyRequest := &helloVerifyRequestMsg{
+ vers: VersionDTLS10,
+ cookie: make([]byte, 32),
+ }
+ if _, err := io.ReadFull(c.config.rand(), helloVerifyRequest.cookie); err != nil {
+ c.sendAlert(alertInternalError)
+ return errors.New("dtls: short read from Rand: " + err.Error())
+ }
+ c.writeRecord(recordTypeHandshake, helloVerifyRequest.marshal())
+ c.flushHandshake()
+
+ if err := c.simulatePacketLoss(nil); err != nil {
+ return err
+ }
+ msg, err := c.readHandshake()
+ if err != nil {
+ return err
+ }
+ newClientHello, ok := msg.(*clientHelloMsg)
+ if !ok {
+ c.sendAlert(alertUnexpectedMessage)
+ return unexpectedMessageError(hs.clientHello, msg)
+ }
+ if !bytes.Equal(newClientHello.cookie, helloVerifyRequest.cookie) {
+ return errors.New("dtls: invalid cookie")
+ }
+
+ // Apart from the cookie, the two ClientHellos must
+ // match. Note that clientHello.equal compares the
+ // serialization, so we make a copy.
+ oldClientHelloCopy := *hs.clientHello
+ oldClientHelloCopy.raw = nil
+ oldClientHelloCopy.cookie = nil
+ newClientHelloCopy := *newClientHello
+ newClientHelloCopy.raw = nil
+ newClientHelloCopy.cookie = nil
+ if !oldClientHelloCopy.equal(&newClientHelloCopy) {
+ return errors.New("dtls: retransmitted ClientHello does not match")
+ }
+ hs.clientHello = newClientHello
+ }
+
+ if config.Bugs.RequireSameRenegoClientVersion && c.clientVersion != 0 {
+ if c.clientVersion != hs.clientHello.vers {
+ return fmt.Errorf("tls: client offered different version on renego")
+ }
+ }
+
+ c.clientVersion = hs.clientHello.vers
+
+ // Use the versions extension if supplied, otherwise use the legacy ClientHello version.
+ if len(hs.clientHello.supportedVersions) == 0 {
+ if c.isDTLS {
+ if hs.clientHello.vers <= VersionDTLS12 {
+ hs.clientHello.supportedVersions = append(hs.clientHello.supportedVersions, VersionDTLS12)
+ }
+ if hs.clientHello.vers <= VersionDTLS10 {
+ hs.clientHello.supportedVersions = append(hs.clientHello.supportedVersions, VersionDTLS10)
+ }
+ } else {
+ if hs.clientHello.vers >= VersionTLS12 {
+ hs.clientHello.supportedVersions = append(hs.clientHello.supportedVersions, VersionTLS12)
+ }
+ if hs.clientHello.vers >= VersionTLS11 {
+ hs.clientHello.supportedVersions = append(hs.clientHello.supportedVersions, VersionTLS11)
+ }
+ if hs.clientHello.vers >= VersionTLS10 {
+ hs.clientHello.supportedVersions = append(hs.clientHello.supportedVersions, VersionTLS10)
+ }
+ if hs.clientHello.vers >= VersionSSL30 {
+ hs.clientHello.supportedVersions = append(hs.clientHello.supportedVersions, VersionSSL30)
+ }
+ }
+ } else if config.Bugs.ExpectGREASE && !containsGREASE(hs.clientHello.supportedVersions) {
+ return errors.New("tls: no GREASE version value found")
+ }
+
+ if !c.haveVers {
+ if config.Bugs.NegotiateVersion != 0 {
+ c.wireVersion = config.Bugs.NegotiateVersion
+ } else {
+ var found bool
+ for _, vers := range hs.clientHello.supportedVersions {
+ if _, ok := config.isSupportedVersion(vers, c.isDTLS); ok {
+ c.wireVersion = vers
+ found = true
+ break
+ }
+ }
+ if !found {
+ c.sendAlert(alertProtocolVersion)
+ return errors.New("tls: client did not offer any supported protocol versions")
+ }
+ }
+ } else if config.Bugs.NegotiateVersionOnRenego != 0 {
+ c.wireVersion = config.Bugs.NegotiateVersionOnRenego
+ }
+
+ c.vers, ok = wireToVersion(c.wireVersion, c.isDTLS)
+ if !ok {
+ panic("Could not map wire version")
+ }
+ c.haveVers = true
+
+ clientProtocol, ok := wireToVersion(c.clientVersion, c.isDTLS)
+
+ // Reject < 1.2 ClientHellos with signature_algorithms.
+ if ok && clientProtocol < VersionTLS12 && len(hs.clientHello.signatureAlgorithms) > 0 {
+ return fmt.Errorf("tls: client included signature_algorithms before TLS 1.2")
+ }
+
+ // Check the client cipher list is consistent with the version.
+ if ok && clientProtocol < VersionTLS12 {
+ for _, id := range hs.clientHello.cipherSuites {
+ if isTLS12Cipher(id) {
+ return fmt.Errorf("tls: client offered TLS 1.2 cipher before TLS 1.2")
+ }
+ }
+ }
+
+ if config.Bugs.ExpectNoTLS12Session {
+ if len(hs.clientHello.sessionId) > 0 && c.vers >= VersionTLS13 {
+ return fmt.Errorf("tls: client offered an unexpected session ID")
+ }
+ if len(hs.clientHello.sessionTicket) > 0 {
+ return fmt.Errorf("tls: client offered an unexpected session ticket")
+ }
+ }
+
+ if config.Bugs.ExpectNoTLS13PSK && len(hs.clientHello.pskIdentities) > 0 {
+ return fmt.Errorf("tls: client offered unexpected PSK identities")
+ }
+
+ var scsvFound bool
+ for _, cipherSuite := range hs.clientHello.cipherSuites {
+ if cipherSuite == fallbackSCSV {
+ scsvFound = true
+ break
+ }
+ }
+
+ if !scsvFound && config.Bugs.FailIfNotFallbackSCSV {
+ return errors.New("tls: no fallback SCSV found when expected")
+ } else if scsvFound && !config.Bugs.FailIfNotFallbackSCSV {
+ return errors.New("tls: fallback SCSV found when not expected")
+ }
+
+ if config.Bugs.ExpectGREASE && !containsGREASE(hs.clientHello.cipherSuites) {
+ return errors.New("tls: no GREASE cipher suite value found")
+ }
+
+ var greaseFound bool
+ for _, curve := range hs.clientHello.supportedCurves {
+ if isGREASEValue(uint16(curve)) {
+ greaseFound = true
+ break
+ }
+ }
+
+ if !greaseFound && config.Bugs.ExpectGREASE {
+ return errors.New("tls: no GREASE curve value found")
+ }
+
+ if len(hs.clientHello.keyShares) > 0 {
+ greaseFound = false
+ for _, keyShare := range hs.clientHello.keyShares {
+ if isGREASEValue(uint16(keyShare.group)) {
+ greaseFound = true
+ break
+ }
+ }
+
+ if !greaseFound && config.Bugs.ExpectGREASE {
+ return errors.New("tls: no GREASE curve value found")
+ }
+ }
+
+ if expected := hs.clientHello.dummyPQPaddingLen; expected != config.Bugs.ExpectDummyPQPaddingLength {
+ return fmt.Errorf("tls: expected dummy PQ padding extension of length %d, but got one of length %d", expected, config.Bugs.ExpectDummyPQPaddingLength)
+ }
+
+ applyBugsToClientHello(hs.clientHello, config)
+
+ return nil
+}
+
+func applyBugsToClientHello(clientHello *clientHelloMsg, config *Config) {
+ if config.Bugs.IgnorePeerSignatureAlgorithmPreferences {
+ clientHello.signatureAlgorithms = config.signSignatureAlgorithms()
+ }
+ if config.Bugs.IgnorePeerCurvePreferences {
+ clientHello.supportedCurves = config.curvePreferences()
+ }
+ if config.Bugs.IgnorePeerCipherPreferences {
+ clientHello.cipherSuites = config.cipherSuites()
+ }
+}
+
+func (hs *serverHandshakeState) doTLS13Handshake() error {
+ c := hs.c
+ config := c.config
+
+ // We've read the ClientHello, so the next record must be preceded with ChangeCipherSpec.
+ c.expectTLS13ChangeCipherSpec = true
+
+ hs.hello = &serverHelloMsg{
+ isDTLS: c.isDTLS,
+ vers: c.wireVersion,
+ sessionId: hs.clientHello.sessionId,
+ compressionMethod: config.Bugs.SendCompressionMethod,
+ versOverride: config.Bugs.SendServerHelloVersion,
+ supportedVersOverride: config.Bugs.SendServerSupportedExtensionVersion,
+ customExtension: config.Bugs.CustomUnencryptedExtension,
+ unencryptedALPN: config.Bugs.SendUnencryptedALPN,
+ }
+
+ hs.hello.random = make([]byte, 32)
+ if _, err := io.ReadFull(config.rand(), hs.hello.random); err != nil {
+ c.sendAlert(alertInternalError)
+ return err
+ }
+
+ // TLS 1.3 forbids clients from advertising any non-null compression.
+ if len(hs.clientHello.compressionMethods) != 1 || hs.clientHello.compressionMethods[0] != compressionNone {
+ return errors.New("tls: client sent compression method other than null for TLS 1.3")
+ }
+
+ // Prepare an EncryptedExtensions message, but do not send it yet.
+ encryptedExtensions := new(encryptedExtensionsMsg)
+ encryptedExtensions.empty = config.Bugs.EmptyEncryptedExtensions
+ if err := hs.processClientExtensions(&encryptedExtensions.extensions); err != nil {
+ return err
+ }
+
+ // Select the cipher suite.
+ var preferenceList, supportedList []uint16
+ if config.PreferServerCipherSuites {
+ preferenceList = config.cipherSuites()
+ supportedList = hs.clientHello.cipherSuites
+ } else {
+ preferenceList = hs.clientHello.cipherSuites
+ supportedList = config.cipherSuites()
+ }
+
+ for _, id := range preferenceList {
+ if hs.suite = c.tryCipherSuite(id, supportedList, c.vers, true, true); hs.suite != nil {
+ break
+ }
+ }
+
+ if hs.suite == nil {
+ c.sendAlert(alertHandshakeFailure)
+ return errors.New("tls: no cipher suite supported by both client and server")
+ }
+
+ hs.hello.cipherSuite = hs.suite.id
+ if c.config.Bugs.SendCipherSuite != 0 {
+ hs.hello.cipherSuite = c.config.Bugs.SendCipherSuite
+ }
+
+ hs.finishedHash = newFinishedHash(c.wireVersion, c.isDTLS, hs.suite)
+ hs.finishedHash.discardHandshakeBuffer()
+ hs.writeClientHash(hs.clientHello.marshal())
+
+ supportedCurve := false
+ var selectedCurve CurveID
+ preferredCurves := config.curvePreferences()
+Curves:
+ for _, curve := range hs.clientHello.supportedCurves {
+ for _, supported := range preferredCurves {
+ if supported == curve {
+ supportedCurve = true
+ selectedCurve = curve
+ break Curves
+ }
+ }
+ }
+
+ if !supportedCurve {
+ c.sendAlert(alertHandshakeFailure)
+ return errors.New("tls: no curve supported by both client and server")
+ }
+
+ pskIdentities := hs.clientHello.pskIdentities
+ pskKEModes := hs.clientHello.pskKEModes
+
+ if len(pskIdentities) == 0 && len(hs.clientHello.sessionTicket) > 0 && c.config.Bugs.AcceptAnySession {
+ psk := pskIdentity{
+ ticket: hs.clientHello.sessionTicket,
+ }
+ pskIdentities = []pskIdentity{psk}
+ pskKEModes = []byte{pskDHEKEMode}
+ }
+
+ var pskIndex int
+ foundKEMode := bytes.IndexByte(pskKEModes, pskDHEKEMode) >= 0
+ if foundKEMode && !config.SessionTicketsDisabled {
+ for i, pskIdentity := range pskIdentities {
+ // TODO(svaldez): Check the obfuscatedTicketAge before accepting 0-RTT.
+ sessionState, ok := c.decryptTicket(pskIdentity.ticket)
+ if !ok {
+ continue
+ }
+
+ if !config.Bugs.AcceptAnySession {
+ if sessionState.vers != c.vers {
+ continue
+ }
+ if sessionState.ticketExpiration.Before(c.config.time()) {
+ continue
+ }
+ sessionCipher := cipherSuiteFromID(sessionState.cipherSuite)
+ if sessionCipher == nil || sessionCipher.hash() != hs.suite.hash() {
+ continue
+ }
+ }
+
+ clientTicketAge := time.Duration(uint32(pskIdentity.obfuscatedTicketAge-sessionState.ticketAgeAdd)) * time.Millisecond
+ if config.Bugs.ExpectTicketAge != 0 && clientTicketAge != config.Bugs.ExpectTicketAge {
+ c.sendAlert(alertHandshakeFailure)
+ return errors.New("tls: invalid ticket age")
+ }
+
+ hs.sessionState = sessionState
+ hs.hello.hasPSKIdentity = true
+ hs.hello.pskIdentity = uint16(i)
+ pskIndex = i
+ if config.Bugs.SelectPSKIdentityOnResume != 0 {
+ hs.hello.pskIdentity = config.Bugs.SelectPSKIdentityOnResume
+ }
+ c.didResume = true
+ break
+ }
+ }
+
+ if config.Bugs.AlwaysSelectPSKIdentity {
+ hs.hello.hasPSKIdentity = true
+ hs.hello.pskIdentity = 0
+ }
+
+ // Verify the PSK binder. Note there may not be a PSK binder if
+ // AcceptAnyBinder is set. See https://crbug.com/boringssl/115.
+ if hs.sessionState != nil && !config.Bugs.AcceptAnySession {
+ binderToVerify := hs.clientHello.pskBinders[pskIndex]
+ if err := verifyPSKBinder(c.wireVersion, hs.clientHello, hs.sessionState, binderToVerify, []byte{}, []byte{}); err != nil {
+ return err
+ }
+ }
+
+ // Resolve PSK and compute the early secret.
+ if hs.sessionState != nil {
+ hs.finishedHash.addEntropy(hs.sessionState.masterSecret)
+ } else {
+ hs.finishedHash.addEntropy(hs.finishedHash.zeroSecret())
+ }
+
+ hs.hello.hasKeyShare = true
+ if hs.sessionState != nil && config.Bugs.NegotiatePSKResumption {
+ hs.hello.hasKeyShare = false
+ }
+ if config.Bugs.MissingKeyShare {
+ hs.hello.hasKeyShare = false
+ }
+
+ firstHelloRetryRequest := true
+
+ResendHelloRetryRequest:
+ var sendHelloRetryRequest bool
+ cipherSuite := hs.suite.id
+ if config.Bugs.SendHelloRetryRequestCipherSuite != 0 {
+ cipherSuite = config.Bugs.SendHelloRetryRequestCipherSuite
+ }
+ helloRetryRequest := &helloRetryRequestMsg{
+ vers: c.wireVersion,
+ sessionId: hs.clientHello.sessionId,
+ cipherSuite: cipherSuite,
+ compressionMethod: config.Bugs.SendCompressionMethod,
+ 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 {
+ if err := hs.finishedHash.UpdateForHelloRetryRequest(); err != nil {
+ return err
+ }
+
+ oldClientHelloBytes := hs.clientHello.marshal()
+ hs.writeServerHash(helloRetryRequest.marshal())
+ c.writeRecord(recordTypeHandshake, helloRetryRequest.marshal())
+ c.flushHandshake()
+
+ if !c.config.Bugs.SkipChangeCipherSpec {
+ c.writeRecord(recordTypeChangeCipherSpec, []byte{1})
+ }
+
+ if hs.clientHello.hasEarlyData {
+ c.skipEarlyData = true
+ }
+
+ // 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())
+
+ if config.Bugs.ExpectNoTLS13PSKAfterHRR && len(newClientHello.pskIdentities) > 0 {
+ return fmt.Errorf("tls: client offered unexpected PSK identities after HelloRetryRequest")
+ }
+
+ if newClientHello.hasEarlyData {
+ return errors.New("tls: EarlyData sent in new ClientHello")
+ }
+
+ applyBugsToClientHello(newClientHello, config)
+
+ // 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) {
+ newClientHelloCopy.pskIdentities = oldClientHelloCopy.pskIdentities
+ } else {
+ 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
+ newClientHelloCopy.hasEarlyData = oldClientHelloCopy.hasEarlyData
+
+ 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]
+ if err := verifyPSKBinder(c.wireVersion, newClientHello, hs.sessionState, binderToVerify, oldClientHelloBytes, helloRetryRequest.marshal()); err != nil {
+ return err
+ }
+ }
+ }
+
+ // Decide whether or not to accept early data.
+ if !sendHelloRetryRequest && hs.clientHello.hasEarlyData {
+ if !config.Bugs.AlwaysRejectEarlyData && hs.sessionState != nil {
+ if c.clientProtocol == string(hs.sessionState.earlyALPN) || config.Bugs.AlwaysAcceptEarlyData {
+ encryptedExtensions.extensions.hasEarlyData = true
+ }
+ }
+ if encryptedExtensions.extensions.hasEarlyData {
+ earlyTrafficSecret := hs.finishedHash.deriveSecret(earlyTrafficLabel)
+ c.earlyExporterSecret = hs.finishedHash.deriveSecret(earlyExporterLabel)
+
+ if err := c.useInTrafficSecret(c.wireVersion, hs.suite, earlyTrafficSecret); err != nil {
+ return err
+ }
+
+ c.earlyCipherSuite = hs.suite
+ expectEarlyData := config.Bugs.ExpectEarlyData
+ if n := config.Bugs.ExpectEarlyKeyingMaterial; n > 0 {
+ exporter, err := c.ExportEarlyKeyingMaterial(n, []byte(config.Bugs.ExpectEarlyKeyingLabel), []byte(config.Bugs.ExpectEarlyKeyingContext))
+ if err != nil {
+ return err
+ }
+ expectEarlyData = append([][]byte{exporter}, expectEarlyData...)
+ }
+
+ for _, expectedMsg := range expectEarlyData {
+ if err := c.readRecord(recordTypeApplicationData); err != nil {
+ return err
+ }
+ msg := c.input.data[c.input.off:]
+ if !bytes.Equal(msg, expectedMsg) {
+ return fmt.Errorf("tls: got early data record %x, wanted %x", msg, expectedMsg)
+ }
+ c.in.freeBlock(c.input)
+ c.input = nil
+ }
+ } else {
+ c.skipEarlyData = true
+ }
+ }
+
+ if config.Bugs.SendEarlyDataExtension {
+ encryptedExtensions.extensions.hasEarlyData = true
+ }
+
+ // Resolve ECDHE and compute the handshake secret.
+ 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, config)
+ 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, config)
+ var err error
+ peerKey, err = curve2.offer(config.rand())
+ if err != nil {
+ return err
+ }
+ } else {
+ peerKey = selectedKeyShare.keyExchange
+ }
+
+ publicKey, ecdheSecret, err := curve.accept(config.rand(), peerKey)
+ if err != nil {
+ c.sendAlert(alertHandshakeFailure)
+ return err
+ }
+ hs.finishedHash.nextSecret()
+ hs.finishedHash.addEntropy(ecdheSecret)
+ 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 {
+ hs.finishedHash.nextSecret()
+ hs.finishedHash.addEntropy(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()
+
+ if !c.config.Bugs.SkipChangeCipherSpec && !sendHelloRetryRequest {
+ c.writeRecord(recordTypeChangeCipherSpec, []byte{1})
+ }
+
+ for i := 0; i < c.config.Bugs.SendExtraChangeCipherSpec; i++ {
+ c.writeRecord(recordTypeChangeCipherSpec, []byte{1})
+ }
+
+ // Switch to handshake traffic keys.
+ serverHandshakeTrafficSecret := hs.finishedHash.deriveSecret(serverHandshakeTrafficLabel)
+ c.useOutTrafficSecret(c.wireVersion, hs.suite, serverHandshakeTrafficSecret)
+ // Derive handshake traffic read key, but don't switch yet.
+ clientHandshakeTrafficSecret := hs.finishedHash.deriveSecret(clientHandshakeTrafficLabel)
+
+ // 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{
+ vers: c.wireVersion,
+ hasSignatureAlgorithm: !config.Bugs.OmitCertificateRequestAlgorithms,
+ hasRequestContext: true,
+ requestContext: config.Bugs.SendRequestContext,
+ customExtension: config.Bugs.SendCustomCertificateRequest,
+ }
+ 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
+ }
+
+ if !config.Bugs.SkipCertificateVerify {
+ 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()
+
+ if encryptedExtensions.extensions.hasEarlyData && !c.skipEarlyData {
+ for _, expectedMsg := range config.Bugs.ExpectLateEarlyData {
+ if err := c.readRecord(recordTypeApplicationData); err != nil {
+ return err
+ }
+ if !bytes.Equal(c.input.data[c.input.off:], expectedMsg) {
+ return errors.New("ExpectLateEarlyData: did not get expected message")
+ }
+ c.in.freeBlock(c.input)
+ c.input = nil
+ }
+ }
+
+ // The various secrets do not incorporate the client's final leg, so
+ // derive them now before updating the handshake context.
+ hs.finishedHash.nextSecret()
+ hs.finishedHash.addEntropy(hs.finishedHash.zeroSecret())
+
+ clientTrafficSecret := hs.finishedHash.deriveSecret(clientApplicationTrafficLabel)
+ serverTrafficSecret := hs.finishedHash.deriveSecret(serverApplicationTrafficLabel)
+ c.exporterSecret = hs.finishedHash.deriveSecret(exporterLabel)
+
+ // Switch to application data keys on write. In particular, any alerts
+ // from the client certificate are sent over these keys.
+ c.useOutTrafficSecret(c.wireVersion, hs.suite, serverTrafficSecret)
+
+ // Send 0.5-RTT messages.
+ for _, halfRTTMsg := range config.Bugs.SendHalfRTTData {
+ if _, err := c.writeRecord(recordTypeApplicationData, halfRTTMsg); err != nil {
+ return err
+ }
+ }
+
+ // Read end_of_early_data.
+ if encryptedExtensions.extensions.hasEarlyData {
+ msg, err := c.readHandshake()
+ if err != nil {
+ return err
+ }
+
+ endOfEarlyData, ok := msg.(*endOfEarlyDataMsg)
+ if !ok {
+ c.sendAlert(alertUnexpectedMessage)
+ return unexpectedMessageError(endOfEarlyData, msg)
+ }
+ hs.writeClientHash(endOfEarlyData.marshal())
+ }
+
+ // Switch input stream to handshake traffic keys.
+ if err := c.useInTrafficSecret(c.wireVersion, hs.suite, clientHandshakeTrafficSecret); err != nil {
+ return err
+ }
+
+ // 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.
+ if err := c.useInTrafficSecret(c.wireVersion, hs.suite, clientTrafficSecret); err != nil {
+ return err
+ }
+
+ c.cipherSuite = hs.suite
+ c.resumptionSecret = hs.finishedHash.deriveSecret(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([]byte{byte(i)})
+ }
+ }
+ 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: c.wireVersion,
+ versOverride: config.Bugs.SendServerHelloVersion,
+ compressionMethod: config.Bugs.SendCompressionMethod,
+ extensions: serverExtensions{
+ supportedVersion: config.Bugs.SendServerSupportedExtensionVersion,
+ },
+ omitExtensions: config.Bugs.OmitExtensions,
+ emptyExtensions: config.Bugs.EmptyExtensions,
+ }
+
+ 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)
+ }
+ if config.Bugs.SendDraftTLS13DowngradeRandom {
+ copy(hs.hello.random[len(hs.hello.random)-8:], downgradeTLS13Draft)
+ }
+
+ if len(hs.clientHello.sessionId) == 0 && c.config.Bugs.ExpectClientHelloSessionID {
+ return false, errors.New("tls: expected non-empty session ID from client")
+ }
+
+ 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)
+ // Ed25519 also uses ECDSA certificates.
+ _, ed25519Ok := hs.cert.PrivateKey.(ed25519.PrivateKey)
+ hs.ecdsaOk = hs.ecdsaOk || ed25519Ok
+
+ // 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
+ }
+ if c.config.Bugs.BadRenegotiationInfoEnd {
+ serverExtensions.secureRenegotiation[len(serverExtensions.secureRenegotiation)-1] ^= 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 cert := config.Bugs.RenegotiationCertificate; c.cipherSuite != nil && cert != nil {
+ hs.cert = cert
+ }
+
+ if len(hs.clientHello.alpnProtocols) > 0 {
+ // We will never offer ALPN as a client on renegotiation
+ // handshakes.
+ if len(c.clientVerify) > 0 {
+ return errors.New("tls: offered ALPN on renegotiation")
+ }
+ 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 len(hs.clientHello.quicTransportParams) > 0 {
+ c.quicTransportParams = hs.clientHello.quicTransportParams
+ serverExtensions.quicTransportParams = c.config.QUICTransportParams
+ }
+
+ 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 config.TokenBindingParams != nil {
+ if !bytes.Equal(config.ExpectTokenBindingParams, hs.clientHello.tokenBindingParams) {
+ return errors.New("client did not send expected token binding params")
+ }
+
+ // For testing, blindly send whatever is set in config, even if
+ // it is invalid.
+ serverExtensions.tokenBindingParams = config.TokenBindingParams
+ serverExtensions.tokenBindingVersion = config.TokenBindingVersion
+ }
+
+ if len(hs.clientHello.tokenBindingParams) > 0 && (!hs.clientHello.extendedMasterSecret || hs.clientHello.secureRenegotiation == nil) {
+ return errors.New("client sent Token Binding without EMS and/or RI")
+ }
+
+ 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 c.config.Bugs.SendSupportedPointFormats != nil {
+ serverExtensions.supportedPoints = c.config.Bugs.SendSupportedPointFormats
+ }
+
+ if c.config.Bugs.SendServerSupportedCurves {
+ serverExtensions.supportedCurves = c.config.curvePreferences()
+ }
+
+ if !hs.clientHello.hasGREASEExtension && config.Bugs.ExpectGREASE {
+ return errors.New("tls: no GREASE extension found")
+ }
+
+ if l := hs.clientHello.dummyPQPaddingLen; l != 0 {
+ serverExtensions.dummyPQPaddingLen = l
+ }
+
+ serverExtensions.serverNameAck = c.config.Bugs.SendServerNameAck
+
+ 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.wireVersion, c.isDTLS, 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
+ }
+
+ if len(c.clientVerify) > 0 && config.Bugs.SendSCTListOnRenegotiation != nil {
+ hs.hello.extensions.sctList = config.Bugs.SendSCTListOnRenegotiation
+ }
+
+ 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())
+ }
+ }
+ if config.Bugs.EchoSessionIDInFullHandshake {
+ hs.hello.sessionId = hs.clientHello.sessionId
+ }
+
+ hs.finishedHash = newFinishedHash(c.wireVersion, c.isDTLS, 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
+ if len(c.clientVerify) > 0 && config.Bugs.SendOCSPResponseOnRenegotiation != nil {
+ certStatus.response = config.Bugs.SendOCSPResponseOnRenegotiation
+ }
+ 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{
+ vers: c.wireVersion,
+ 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 SSL 3.0, no certificate is signaled by a warning
+ // alert which we translate to ssl3NoCertificateMsg.
+ if _, ok := msg.(*ssl3NoCertificateMsg); !ok {
+ return errors.New("tls: client provided neither a certificate nor no_certificate warning alert")
+ }
+ } else {
+ // 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
+ }
+
+ 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.wireVersion, clientCipher, clientHash)
+ c.out.prepareCipherSpec(c.wireVersion, 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)
+ m.vers = c.wireVersion
+ m.isDTLS = c.isDTLS
+ if c.config.Bugs.SendTicketLifetime != 0 {
+ m.ticketLifetime = uint32(c.config.Bugs.SendTicketLifetime / time.Second)
+ }
+
+ 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, isResume bool) 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
+ }
+
+ 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 isResume || (!c.config.Bugs.PackHelloRequestWithFinished && !c.config.Bugs.PackAppDataWithHandshake) {
+ // Defer flushing until Renegotiate() or Write().
+ 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 {
+ pub := getCertificatePublicKey(certs[0])
+ switch pub.(type) {
+ case *ecdsa.PublicKey, *rsa.PublicKey, ed25519.PublicKey:
+ break
+ default:
+ c.sendAlert(alertUnsupportedCertificate)
+ return nil, fmt.Errorf("tls: client's certificate contains an unsupported public key of type %T", pub)
+ }
+ 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{Curve: elliptic.P256(), X: x, Y: 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
+ }
+ 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(version uint16, clientHello *clientHelloMsg, sessionState *sessionState, binderToVerify, firstClientHello, helloRetryRequest []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, version, resumptionPSKBinderLabel, pskCipherSuite, firstClientHello, helloRetryRequest, truncatedHello)
+ if !bytes.Equal(binder, binderToVerify) {
+ return errors.New("tls: PSK binder does not verify")
+ }
+
+ return nil
+}