| // 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 && !isResumptionExperiment(c.wireVersion) { |
| 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") |
| } |
| } |
| |
| 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 |
| |
| hs.hello = &serverHelloMsg{ |
| isDTLS: c.isDTLS, |
| vers: c.wireVersion, |
| sessionId: hs.clientHello.sessionId, |
| 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.vers, 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(hs.clientHello, hs.sessionState, binderToVerify, []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 |
| helloRetryRequest := &helloRetryRequestMsg{ |
| vers: c.wireVersion, |
| duplicateExtensions: config.Bugs.DuplicateHelloRetryRequestExtensions, |
| } |
| |
| if config.Bugs.AlwaysSendHelloRetryRequest { |
| sendHelloRetryRequest = true |
| } |
| |
| if config.Bugs.SendHelloRetryRequestCookie != nil { |
| sendHelloRetryRequest = true |
| helloRetryRequest.cookie = config.Bugs.SendHelloRetryRequestCookie |
| } |
| |
| if len(config.Bugs.CustomHelloRetryRequestExtension) > 0 { |
| sendHelloRetryRequest = true |
| helloRetryRequest.customExtension = config.Bugs.CustomHelloRetryRequestExtension |
| } |
| |
| var selectedKeyShare *keyShareEntry |
| if hs.hello.hasKeyShare { |
| // Look for the key share corresponding to our selected curve. |
| for i := range hs.clientHello.keyShares { |
| if hs.clientHello.keyShares[i].group == selectedCurve { |
| selectedKeyShare = &hs.clientHello.keyShares[i] |
| break |
| } |
| } |
| |
| if config.Bugs.ExpectMissingKeyShare && selectedKeyShare != nil { |
| return errors.New("tls: expected missing key share") |
| } |
| |
| if selectedKeyShare == nil { |
| helloRetryRequest.hasSelectedGroup = true |
| helloRetryRequest.selectedGroup = selectedCurve |
| sendHelloRetryRequest = true |
| } |
| } |
| |
| if config.Bugs.SendHelloRetryRequestCurve != 0 { |
| helloRetryRequest.hasSelectedGroup = true |
| helloRetryRequest.selectedGroup = config.Bugs.SendHelloRetryRequestCurve |
| sendHelloRetryRequest = true |
| } |
| |
| if config.Bugs.SkipHelloRetryRequest { |
| sendHelloRetryRequest = false |
| } |
| |
| if sendHelloRetryRequest { |
| oldClientHelloBytes := hs.clientHello.marshal() |
| hs.writeServerHash(helloRetryRequest.marshal()) |
| c.writeRecord(recordTypeHandshake, helloRetryRequest.marshal()) |
| c.flushHandshake() |
| |
| 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 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) { |
| 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(newClientHello, hs.sessionState, binderToVerify, append(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) |
| if err := c.useInTrafficSecret(c.wireVersion, hs.suite, earlyTrafficSecret); err != nil { |
| return err |
| } |
| |
| for _, expectedMsg := range config.Bugs.ExpectEarlyData { |
| if err := c.readRecord(recordTypeApplicationData); err != nil { |
| return err |
| } |
| if !bytes.Equal(c.input.data[c.input.off:], expectedMsg) { |
| return errors.New("ExpectEarlyData: did not get expected message") |
| } |
| 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) |
| if !ok { |
| panic("tls: server failed to look up curve ID") |
| } |
| c.curveID = selectedCurve |
| |
| var peerKey []byte |
| if config.Bugs.SkipHelloRetryRequest { |
| // If skipping HelloRetryRequest, use a random key to |
| // avoid crashing. |
| curve2, _ := curveForCurveID(selectedCurve) |
| var err error |
| peerKey, err = curve2.offer(config.rand()) |
| if err != nil { |
| return err |
| } |
| } else { |
| peerKey = selectedKeyShare.keyExchange |
| } |
| |
| publicKey, ecdheSecret, err := curve.accept(config.rand(), peerKey) |
| if err != nil { |
| c.sendAlert(alertHandshakeFailure) |
| return err |
| } |
| 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.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 isResumptionExperiment(c.wireVersion) { |
| 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{ |
| hasSignatureAlgorithm: true, |
| hasRequestContext: true, |
| requestContext: config.Bugs.SendRequestContext, |
| } |
| if !config.Bugs.NoSignatureAlgorithms { |
| certReq.signatureAlgorithms = config.verifySignatureAlgorithms() |
| } |
| |
| // An empty list of certificateAuthorities signals to |
| // the client that it may send any certificate in response |
| // to our request. When we know the CAs we trust, then |
| // we can send them down, so that the client can choose |
| // an appropriate certificate to give to us. |
| if config.ClientCAs != nil { |
| certReq.certificateAuthorities = config.ClientCAs.Subjects() |
| } |
| hs.writeServerHash(certReq.marshal()) |
| c.writeRecord(recordTypeHandshake, certReq.marshal()) |
| } |
| |
| certMsg := &certificateMsg{ |
| hasRequestContext: true, |
| } |
| if !config.Bugs.EmptyCertificateList { |
| for i, certData := range hs.cert.Certificate { |
| cert := certificateEntry{ |
| data: certData, |
| } |
| if i == 0 { |
| if hs.clientHello.ocspStapling { |
| cert.ocspResponse = hs.cert.OCSPStaple |
| } |
| if hs.clientHello.sctListSupported { |
| cert.sctList = hs.cert.SignedCertificateTimestampList |
| } |
| cert.duplicateExtensions = config.Bugs.SendDuplicateCertExtensions |
| cert.extraExtension = config.Bugs.SendExtensionOnCertificate |
| } else { |
| if config.Bugs.SendOCSPOnIntermediates != nil { |
| cert.ocspResponse = config.Bugs.SendOCSPOnIntermediates |
| } |
| if config.Bugs.SendSCTOnIntermediates != nil { |
| cert.sctList = config.Bugs.SendSCTOnIntermediates |
| } |
| } |
| certMsg.certificates = append(certMsg.certificates, cert) |
| } |
| } |
| certMsgBytes := certMsg.marshal() |
| hs.writeServerHash(certMsgBytes) |
| c.writeRecord(recordTypeHandshake, certMsgBytes) |
| |
| certVerify := &certificateVerifyMsg{ |
| hasSignatureAlgorithm: true, |
| } |
| |
| // Determine the hash to sign. |
| privKey := hs.cert.PrivateKey |
| |
| var err error |
| certVerify.signatureAlgorithm, err = selectSignatureAlgorithm(c.vers, privKey, config, hs.clientHello.signatureAlgorithms) |
| if err != nil { |
| c.sendAlert(alertInternalError) |
| return err |
| } |
| |
| input := hs.finishedHash.certificateVerifyInput(serverCertificateVerifyContextTLS13) |
| certVerify.signature, err = signMessage(c.vers, privKey, c.config, certVerify.signatureAlgorithm, input) |
| if err != nil { |
| c.sendAlert(alertInternalError) |
| return err |
| } |
| |
| if config.Bugs.SendSignatureAlgorithm != 0 { |
| certVerify.signatureAlgorithm = config.Bugs.SendSignatureAlgorithm |
| } |
| |
| 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.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 alert. |
| if encryptedExtensions.extensions.hasEarlyData { |
| if err := c.readRecord(recordTypeAlert); err != errEndOfEarlyDataAlert { |
| if err == nil { |
| panic("readRecord(recordTypeAlert) returned nil") |
| } |
| return err |
| } |
| } |
| |
| if isResumptionClientCCSExperiment(c.wireVersion) && !c.skipEarlyData { |
| if err := c.readRecord(recordTypeChangeCipherSpec); err != nil { |
| return err |
| } |
| } |
| |
| // 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() |
| } |
| } |
| 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 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 c.vers < VersionTLS13 || config.Bugs.NegotiateEMSAtAllVersions { |
| disableEMS := config.Bugs.NoExtendedMasterSecret |
| if c.cipherSuite != nil { |
| disableEMS = config.Bugs.NoExtendedMasterSecretOnRenegotiation |
| } |
| serverExtensions.extendedMasterSecret = c.vers >= VersionTLS10 && hs.clientHello.extendedMasterSecret && !disableEMS |
| } |
| |
| if hs.clientHello.channelIDSupported && config.RequestChannelID { |
| serverExtensions.channelIDRequested = true |
| } |
| |
| if hs.clientHello.srtpProtectionProfiles != nil { |
| SRTPLoop: |
| for _, p1 := range c.config.SRTPProtectionProfiles { |
| for _, p2 := range hs.clientHello.srtpProtectionProfiles { |
| if p1 == p2 { |
| serverExtensions.srtpProtectionProfile = p1 |
| c.srtpProtectionProfile = p1 |
| break SRTPLoop |
| } |
| } |
| } |
| } |
| |
| if c.config.Bugs.SendSRTPProtectionProfile != 0 { |
| serverExtensions.srtpProtectionProfile = c.config.Bugs.SendSRTPProtectionProfile |
| } |
| |
| if expected := c.config.Bugs.ExpectedCustomExtension; expected != nil { |
| if hs.clientHello.customExtension != *expected { |
| return fmt.Errorf("tls: bad custom extension contents %q", hs.clientHello.customExtension) |
| } |
| } |
| serverExtensions.customExtension = config.Bugs.CustomExtension |
| |
| if c.config.Bugs.AdvertiseTicketExtension { |
| serverExtensions.ticketSupported = true |
| } |
| |
| if 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") |
| } |
| |
| 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.vers, hs.suite) |
| hs.finishedHash.discardHandshakeBuffer() |
| hs.writeClientHash(hs.clientHello.marshal()) |
| hs.writeServerHash(hs.hello.marshal()) |
| |
| c.writeRecord(recordTypeHandshake, hs.hello.marshal()) |
| |
| if len(hs.sessionState.certificates) > 0 { |
| if _, err := hs.processCertsFromClient(hs.sessionState.certificates); err != nil { |
| return err |
| } |
| } |
| |
| hs.masterSecret = hs.sessionState.masterSecret |
| c.extendedMasterSecret = hs.sessionState.extendedMasterSecret |
| |
| return nil |
| } |
| |
| func (hs *serverHandshakeState) doFullHandshake() error { |
| config := hs.c.config |
| c := hs.c |
| |
| isPSK := hs.suite.flags&suitePSK != 0 |
| if !isPSK && hs.clientHello.ocspStapling && len(hs.cert.OCSPStaple) > 0 { |
| hs.hello.extensions.ocspStapling = true |
| } |
| |
| if hs.clientHello.sctListSupported && len(hs.cert.SignedCertificateTimestampList) > 0 { |
| hs.hello.extensions.sctList = hs.cert.SignedCertificateTimestampList |
| } |
| |
| 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()) |
| } |
| } |
| |
| hs.finishedHash = newFinishedHash(c.vers, hs.suite) |
| hs.writeClientHash(hs.clientHello.marshal()) |
| hs.writeServerHash(hs.hello.marshal()) |
| |
| if config.Bugs.SendSNIWarningAlert { |
| c.SendAlert(alertLevelWarning, alertUnrecognizedName) |
| } |
| |
| c.writeRecord(recordTypeHandshake, hs.hello.marshal()) |
| |
| if !isPSK { |
| certMsg := new(certificateMsg) |
| if !config.Bugs.EmptyCertificateList { |
| for _, certData := range hs.cert.Certificate { |
| certMsg.certificates = append(certMsg.certificates, certificateEntry{ |
| data: certData, |
| }) |
| } |
| } |
| if !config.Bugs.UnauthenticatedECDH { |
| certMsgBytes := certMsg.marshal() |
| hs.writeServerHash(certMsgBytes) |
| c.writeRecord(recordTypeHandshake, certMsgBytes) |
| } |
| } |
| |
| if hs.hello.extensions.ocspStapling && !c.config.Bugs.SkipCertificateStatus { |
| certStatus := new(certificateStatusMsg) |
| certStatus.statusType = statusTypeOCSP |
| certStatus.response = hs.cert.OCSPStaple |
| 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{ |
| 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) |
| 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 |
| } |
| if c.isDTLS && candidate.flags&suiteNoDTLS != 0 { |
| continue |
| } |
| return candidate |
| } |
| } |
| |
| return nil |
| } |
| |
| func isTLS12Cipher(id uint16) bool { |
| for _, cipher := range cipherSuites { |
| if cipher.id != id { |
| continue |
| } |
| return cipher.flags&suiteTLS12 != 0 |
| } |
| // Unknown cipher. |
| return false |
| } |
| |
| func isGREASEValue(val uint16) bool { |
| return val&0x0f0f == 0x0a0a && val&0xff == val>>8 |
| } |
| |
| func verifyPSKBinder(clientHello *clientHelloMsg, sessionState *sessionState, binderToVerify, transcript []byte) error { |
| binderLen := 2 |
| for _, binder := range clientHello.pskBinders { |
| binderLen += 1 + len(binder) |
| } |
| |
| truncatedHello := clientHello.marshal() |
| truncatedHello = truncatedHello[:len(truncatedHello)-binderLen] |
| pskCipherSuite := cipherSuiteFromID(sessionState.cipherSuite) |
| if pskCipherSuite == nil { |
| return errors.New("tls: Unknown cipher suite for PSK in session") |
| } |
| |
| binder := computePSKBinder(sessionState.masterSecret, resumptionPSKBinderLabel, pskCipherSuite, transcript, truncatedHello) |
| if !bytes.Equal(binder, binderToVerify) { |
| return errors.New("tls: PSK binder does not verify") |
| } |
| |
| return nil |
| } |
