272 lines
10 KiB
Go
272 lines
10 KiB
Go
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package dtls
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import (
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"bytes"
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"context"
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"github.com/pion/dtls/v2/pkg/crypto/elliptic"
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"github.com/pion/dtls/v2/pkg/crypto/prf"
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"github.com/pion/dtls/v2/pkg/protocol"
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"github.com/pion/dtls/v2/pkg/protocol/alert"
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"github.com/pion/dtls/v2/pkg/protocol/extension"
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"github.com/pion/dtls/v2/pkg/protocol/handshake"
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"github.com/pion/dtls/v2/pkg/protocol/recordlayer"
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)
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func flight3Parse(ctx context.Context, c flightConn, state *State, cache *handshakeCache, cfg *handshakeConfig) (flightVal, *alert.Alert, error) { //nolint:gocognit
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// Clients may receive multiple HelloVerifyRequest messages with different cookies.
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// Clients SHOULD handle this by sending a new ClientHello with a cookie in response
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// to the new HelloVerifyRequest. RFC 6347 Section 4.2.1
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seq, msgs, ok := cache.fullPullMap(state.handshakeRecvSequence,
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handshakeCachePullRule{handshake.TypeHelloVerifyRequest, cfg.initialEpoch, false, true},
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)
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if ok {
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if h, msgOk := msgs[handshake.TypeHelloVerifyRequest].(*handshake.MessageHelloVerifyRequest); msgOk {
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// DTLS 1.2 clients must not assume that the server will use the protocol version
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// specified in HelloVerifyRequest message. RFC 6347 Section 4.2.1
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if !h.Version.Equal(protocol.Version1_0) && !h.Version.Equal(protocol.Version1_2) {
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return 0, &alert.Alert{Level: alert.Fatal, Description: alert.ProtocolVersion}, errUnsupportedProtocolVersion
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}
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state.cookie = append([]byte{}, h.Cookie...)
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state.handshakeRecvSequence = seq
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return flight3, nil, nil
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}
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}
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_, msgs, ok = cache.fullPullMap(state.handshakeRecvSequence,
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handshakeCachePullRule{handshake.TypeServerHello, cfg.initialEpoch, false, false},
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)
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if !ok {
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// Don't have enough messages. Keep reading
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return 0, nil, nil
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}
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if h, msgOk := msgs[handshake.TypeServerHello].(*handshake.MessageServerHello); msgOk {
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if !h.Version.Equal(protocol.Version1_2) {
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return 0, &alert.Alert{Level: alert.Fatal, Description: alert.ProtocolVersion}, errUnsupportedProtocolVersion
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}
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for _, v := range h.Extensions {
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switch e := v.(type) {
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case *extension.UseSRTP:
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profile, found := findMatchingSRTPProfile(e.ProtectionProfiles, cfg.localSRTPProtectionProfiles)
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if !found {
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return 0, &alert.Alert{Level: alert.Fatal, Description: alert.IllegalParameter}, errClientNoMatchingSRTPProfile
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}
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state.srtpProtectionProfile = profile
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case *extension.UseExtendedMasterSecret:
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if cfg.extendedMasterSecret != DisableExtendedMasterSecret {
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state.extendedMasterSecret = true
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}
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case *extension.ALPN:
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if len(e.ProtocolNameList) > 1 { // This should be exactly 1, the zero case is handle when unmarshalling
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return 0, &alert.Alert{Level: alert.Fatal, Description: alert.InternalError}, extension.ErrALPNInvalidFormat // Meh, internal error?
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}
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state.NegotiatedProtocol = e.ProtocolNameList[0]
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}
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}
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if cfg.extendedMasterSecret == RequireExtendedMasterSecret && !state.extendedMasterSecret {
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return 0, &alert.Alert{Level: alert.Fatal, Description: alert.InsufficientSecurity}, errClientRequiredButNoServerEMS
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}
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if len(cfg.localSRTPProtectionProfiles) > 0 && state.srtpProtectionProfile == 0 {
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return 0, &alert.Alert{Level: alert.Fatal, Description: alert.InsufficientSecurity}, errRequestedButNoSRTPExtension
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}
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remoteCipherSuite := cipherSuiteForID(CipherSuiteID(*h.CipherSuiteID), cfg.customCipherSuites)
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if remoteCipherSuite == nil {
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return 0, &alert.Alert{Level: alert.Fatal, Description: alert.InsufficientSecurity}, errCipherSuiteNoIntersection
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}
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selectedCipherSuite, found := findMatchingCipherSuite([]CipherSuite{remoteCipherSuite}, cfg.localCipherSuites)
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if !found {
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return 0, &alert.Alert{Level: alert.Fatal, Description: alert.InsufficientSecurity}, errInvalidCipherSuite
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}
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state.cipherSuite = selectedCipherSuite
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state.remoteRandom = h.Random
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cfg.log.Tracef("[handshake] use cipher suite: %s", selectedCipherSuite.String())
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if len(h.SessionID) > 0 && bytes.Equal(state.SessionID, h.SessionID) {
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return handleResumption(ctx, c, state, cache, cfg)
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}
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if len(state.SessionID) > 0 {
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cfg.log.Tracef("[handshake] clean old session : %s", state.SessionID)
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if err := cfg.sessionStore.Del(state.SessionID); err != nil {
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return 0, &alert.Alert{Level: alert.Fatal, Description: alert.InternalError}, err
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}
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}
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if cfg.sessionStore == nil {
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state.SessionID = []byte{}
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} else {
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state.SessionID = h.SessionID
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}
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state.masterSecret = []byte{}
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}
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if cfg.localPSKCallback != nil {
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seq, msgs, ok = cache.fullPullMap(state.handshakeRecvSequence+1,
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handshakeCachePullRule{handshake.TypeServerKeyExchange, cfg.initialEpoch, false, true},
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handshakeCachePullRule{handshake.TypeServerHelloDone, cfg.initialEpoch, false, false},
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)
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} else {
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seq, msgs, ok = cache.fullPullMap(state.handshakeRecvSequence+1,
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handshakeCachePullRule{handshake.TypeCertificate, cfg.initialEpoch, false, true},
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handshakeCachePullRule{handshake.TypeServerKeyExchange, cfg.initialEpoch, false, false},
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handshakeCachePullRule{handshake.TypeCertificateRequest, cfg.initialEpoch, false, true},
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handshakeCachePullRule{handshake.TypeServerHelloDone, cfg.initialEpoch, false, false},
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)
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}
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if !ok {
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// Don't have enough messages. Keep reading
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return 0, nil, nil
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}
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state.handshakeRecvSequence = seq
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if h, ok := msgs[handshake.TypeCertificate].(*handshake.MessageCertificate); ok {
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state.PeerCertificates = h.Certificate
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} else if state.cipherSuite.AuthenticationType() == CipherSuiteAuthenticationTypeCertificate {
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return 0, &alert.Alert{Level: alert.Fatal, Description: alert.NoCertificate}, errInvalidCertificate
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}
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if h, ok := msgs[handshake.TypeServerKeyExchange].(*handshake.MessageServerKeyExchange); ok {
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alertPtr, err := handleServerKeyExchange(c, state, cfg, h)
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if err != nil {
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return 0, alertPtr, err
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}
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}
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if _, ok := msgs[handshake.TypeCertificateRequest].(*handshake.MessageCertificateRequest); ok {
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state.remoteRequestedCertificate = true
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}
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return flight5, nil, nil
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}
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func handleResumption(ctx context.Context, c flightConn, state *State, cache *handshakeCache, cfg *handshakeConfig) (flightVal, *alert.Alert, error) {
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if err := state.initCipherSuite(); err != nil {
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return 0, &alert.Alert{Level: alert.Fatal, Description: alert.InternalError}, err
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}
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// Now, encrypted packets can be handled
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if err := c.handleQueuedPackets(ctx); err != nil {
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return 0, &alert.Alert{Level: alert.Fatal, Description: alert.InternalError}, err
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}
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_, msgs, ok := cache.fullPullMap(state.handshakeRecvSequence+1,
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handshakeCachePullRule{handshake.TypeFinished, cfg.initialEpoch + 1, false, false},
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)
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if !ok {
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// No valid message received. Keep reading
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return 0, nil, nil
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}
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var finished *handshake.MessageFinished
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if finished, ok = msgs[handshake.TypeFinished].(*handshake.MessageFinished); !ok {
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return 0, &alert.Alert{Level: alert.Fatal, Description: alert.InternalError}, nil
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}
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plainText := cache.pullAndMerge(
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handshakeCachePullRule{handshake.TypeClientHello, cfg.initialEpoch, true, false},
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handshakeCachePullRule{handshake.TypeServerHello, cfg.initialEpoch, false, false},
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)
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expectedVerifyData, err := prf.VerifyDataServer(state.masterSecret, plainText, state.cipherSuite.HashFunc())
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if err != nil {
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return 0, &alert.Alert{Level: alert.Fatal, Description: alert.InternalError}, err
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}
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if !bytes.Equal(expectedVerifyData, finished.VerifyData) {
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return 0, &alert.Alert{Level: alert.Fatal, Description: alert.HandshakeFailure}, errVerifyDataMismatch
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}
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clientRandom := state.localRandom.MarshalFixed()
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cfg.writeKeyLog(keyLogLabelTLS12, clientRandom[:], state.masterSecret)
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return flight5b, nil, nil
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}
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func handleServerKeyExchange(_ flightConn, state *State, cfg *handshakeConfig, h *handshake.MessageServerKeyExchange) (*alert.Alert, error) {
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var err error
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if cfg.localPSKCallback != nil {
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var psk []byte
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if psk, err = cfg.localPSKCallback(h.IdentityHint); err != nil {
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return &alert.Alert{Level: alert.Fatal, Description: alert.InternalError}, err
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}
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state.IdentityHint = h.IdentityHint
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state.preMasterSecret = prf.PSKPreMasterSecret(psk)
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} else {
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if state.localKeypair, err = elliptic.GenerateKeypair(h.NamedCurve); err != nil {
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return &alert.Alert{Level: alert.Fatal, Description: alert.InternalError}, err
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}
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if state.preMasterSecret, err = prf.PreMasterSecret(h.PublicKey, state.localKeypair.PrivateKey, state.localKeypair.Curve); err != nil {
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return &alert.Alert{Level: alert.Fatal, Description: alert.InternalError}, err
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}
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}
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return nil, nil
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}
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func flight3Generate(c flightConn, state *State, cache *handshakeCache, cfg *handshakeConfig) ([]*packet, *alert.Alert, error) {
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extensions := []extension.Extension{
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&extension.SupportedSignatureAlgorithms{
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SignatureHashAlgorithms: cfg.localSignatureSchemes,
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},
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&extension.RenegotiationInfo{
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RenegotiatedConnection: 0,
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},
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}
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if cfg.localPSKCallback == nil {
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extensions = append(extensions, []extension.Extension{
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&extension.SupportedEllipticCurves{
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EllipticCurves: []elliptic.Curve{elliptic.X25519, elliptic.P256, elliptic.P384},
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},
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&extension.SupportedPointFormats{
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PointFormats: []elliptic.CurvePointFormat{elliptic.CurvePointFormatUncompressed},
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},
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}...)
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}
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if len(cfg.localSRTPProtectionProfiles) > 0 {
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extensions = append(extensions, &extension.UseSRTP{
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ProtectionProfiles: cfg.localSRTPProtectionProfiles,
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})
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}
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if cfg.extendedMasterSecret == RequestExtendedMasterSecret ||
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cfg.extendedMasterSecret == RequireExtendedMasterSecret {
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extensions = append(extensions, &extension.UseExtendedMasterSecret{
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Supported: true,
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})
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}
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if len(cfg.serverName) > 0 {
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extensions = append(extensions, &extension.ServerName{ServerName: cfg.serverName})
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}
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if len(cfg.supportedProtocols) > 0 {
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extensions = append(extensions, &extension.ALPN{ProtocolNameList: cfg.supportedProtocols})
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}
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return []*packet{
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{
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record: &recordlayer.RecordLayer{
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Header: recordlayer.Header{
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Version: protocol.Version1_2,
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},
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Content: &handshake.Handshake{
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Message: &handshake.MessageClientHello{
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Version: protocol.Version1_2,
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SessionID: state.SessionID,
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Cookie: state.cookie,
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Random: state.localRandom,
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CipherSuiteIDs: cipherSuiteIDs(cfg.localCipherSuites),
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CompressionMethods: defaultCompressionMethods(),
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Extensions: extensions,
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},
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},
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},
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},
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}, nil, nil
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}
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