//go:build with_ech package tls import ( "context" "crypto/tls" "crypto/x509" "encoding/base64" "net" "net/netip" "os" cftls "github.com/sagernet/cloudflare-tls" "github.com/sagernet/sing-box/adapter" "github.com/sagernet/sing-box/option" "github.com/sagernet/sing-dns" E "github.com/sagernet/sing/common/exceptions" mDNS "github.com/miekg/dns" ) type echClientConfig struct { config *cftls.Config } func (e *echClientConfig) NextProtos() []string { return e.config.NextProtos } func (e *echClientConfig) SetNextProtos(nextProto []string) { e.config.NextProtos = nextProto } func (e *echClientConfig) Config() (*STDConfig, error) { return nil, E.New("unsupported usage for ECH") } func (e *echClientConfig) Client(conn net.Conn) Conn { return &echConnWrapper{cftls.Client(conn, e.config)} } type echConnWrapper struct { *cftls.Conn } func (c *echConnWrapper) ConnectionState() tls.ConnectionState { state := c.Conn.ConnectionState() return tls.ConnectionState{ Version: state.Version, HandshakeComplete: state.HandshakeComplete, DidResume: state.DidResume, CipherSuite: state.CipherSuite, NegotiatedProtocol: state.NegotiatedProtocol, NegotiatedProtocolIsMutual: state.NegotiatedProtocolIsMutual, ServerName: state.ServerName, PeerCertificates: state.PeerCertificates, VerifiedChains: state.VerifiedChains, SignedCertificateTimestamps: state.SignedCertificateTimestamps, OCSPResponse: state.OCSPResponse, TLSUnique: state.TLSUnique, } } func newECHClient(router adapter.Router, serverAddress string, options option.OutboundTLSOptions) (Config, error) { var serverName string if options.ServerName != "" { serverName = options.ServerName } else if serverAddress != "" { if _, err := netip.ParseAddr(serverName); err != nil { serverName = serverAddress } } if serverName == "" && !options.Insecure { return nil, E.New("missing server_name or insecure=true") } var tlsConfig cftls.Config if options.DisableSNI { tlsConfig.ServerName = "127.0.0.1" } else { tlsConfig.ServerName = serverName } if options.Insecure { tlsConfig.InsecureSkipVerify = options.Insecure } else if options.DisableSNI { tlsConfig.InsecureSkipVerify = true tlsConfig.VerifyConnection = func(state cftls.ConnectionState) error { verifyOptions := x509.VerifyOptions{ DNSName: serverName, Intermediates: x509.NewCertPool(), } for _, cert := range state.PeerCertificates[1:] { verifyOptions.Intermediates.AddCert(cert) } _, err := state.PeerCertificates[0].Verify(verifyOptions) return err } } if len(options.ALPN) > 0 { tlsConfig.NextProtos = options.ALPN } if options.MinVersion != "" { minVersion, err := ParseTLSVersion(options.MinVersion) if err != nil { return nil, E.Cause(err, "parse min_version") } tlsConfig.MinVersion = minVersion } if options.MaxVersion != "" { maxVersion, err := ParseTLSVersion(options.MaxVersion) if err != nil { return nil, E.Cause(err, "parse max_version") } tlsConfig.MaxVersion = maxVersion } if options.CipherSuites != nil { find: for _, cipherSuite := range options.CipherSuites { for _, tlsCipherSuite := range cftls.CipherSuites() { if cipherSuite == tlsCipherSuite.Name { tlsConfig.CipherSuites = append(tlsConfig.CipherSuites, tlsCipherSuite.ID) continue find } } return nil, E.New("unknown cipher_suite: ", cipherSuite) } } var certificate []byte if options.Certificate != "" { certificate = []byte(options.Certificate) } else if options.CertificatePath != "" { content, err := os.ReadFile(options.CertificatePath) if err != nil { return nil, E.Cause(err, "read certificate") } certificate = content } if len(certificate) > 0 { certPool := x509.NewCertPool() if !certPool.AppendCertsFromPEM(certificate) { return nil, E.New("failed to parse certificate:\n\n", certificate) } tlsConfig.RootCAs = certPool } // ECH Config tlsConfig.ECHEnabled = true tlsConfig.PQSignatureSchemesEnabled = options.ECH.PQSignatureSchemesEnabled tlsConfig.DynamicRecordSizingDisabled = options.ECH.DynamicRecordSizingDisabled if options.ECH.Config != "" { clientConfigContent, err := base64.StdEncoding.DecodeString(options.ECH.Config) if err != nil { return nil, err } clientConfig, err := cftls.UnmarshalECHConfigs(clientConfigContent) if err != nil { return nil, err } tlsConfig.ClientECHConfigs = clientConfig } else { tlsConfig.GetClientECHConfigs = fetchECHClientConfig(router) } return &echClientConfig{&tlsConfig}, nil } func fetchECHClientConfig(router adapter.Router) func(ctx context.Context, serverName string) ([]cftls.ECHConfig, error) { return func(ctx context.Context, serverName string) ([]cftls.ECHConfig, error) { message := &mDNS.Msg{ MsgHdr: mDNS.MsgHdr{ RecursionDesired: true, }, Question: []mDNS.Question{ { Name: serverName + ".", Qtype: mDNS.TypeHTTPS, Qclass: mDNS.ClassINET, }, }, } response, err := router.Exchange(ctx, message) if err != nil { return nil, err } if response.Rcode != mDNS.RcodeSuccess { return nil, dns.RCodeError(response.Rcode) } for _, rr := range response.Answer { switch resource := rr.(type) { case *mDNS.HTTPS: for _, value := range resource.Value { if value.Key().String() == "ech" { echConfig, err := base64.StdEncoding.DecodeString(value.String()) if err != nil { return nil, E.Cause(err, "decode ECH config") } return cftls.UnmarshalECHConfigs(echConfig) } } default: return nil, E.New("unknown resource record type: ", resource.Header().Rrtype) } } return nil, E.New("no ECH config found") } }