func convertTLSConfig(config *transport.TLSConfig) *tls.Config {
var tlsConfig *tls.Config
tlsConfig.Certificates = config.Certificates
tlsConfig.CipherSuites = config.CipherSuites
tlsConfig.RootCAs = config.RootCAs
tlsConfig.CurvePreferences = config.CurvePreferences
return tlsConfig
}
// MakeTLSConfig reduces configs into a single tls.Config.
// If TLS is to be disabled, a nil tls.Config will be returned.
func MakeTLSConfig(configs []*Config) (*tls.Config, error) {
if len(configs) == 0 {
return nil, nil
}
config := new(tls.Config)
ciphersAdded := make(map[uint16]struct{})
curvesAdded := make(map[tls.CurveID]struct{})
configMap := make(configGroup)
for i, cfg := range configs {
if cfg == nil {
// avoid nil pointer dereference below
configs[i] = new(Config)
continue
}
// Key this config by its hostname; this
// overwrites configs with the same hostname
configMap[cfg.Hostname] = cfg
// Can't serve TLS and not-TLS on same port
if i > 0 && cfg.Enabled != configs[i-1].Enabled {
thisConfProto, lastConfProto := "not TLS", "not TLS"
if cfg.Enabled {
thisConfProto = "TLS"
}
if configs[i-1].Enabled {
lastConfProto = "TLS"
}
return nil, fmt.Errorf("cannot multiplex %s (%s) and %s (%s) on same listener",
configs[i-1].Hostname, lastConfProto, cfg.Hostname, thisConfProto)
}
if !cfg.Enabled {
continue
}
// Union cipher suites
for _, ciph := range cfg.Ciphers {
if _, ok := ciphersAdded[ciph]; !ok {
ciphersAdded[ciph] = struct{}{}
config.CipherSuites = append(config.CipherSuites, ciph)
}
}
// Can't resolve conflicting PreferServerCipherSuites settings
if i > 0 && cfg.PreferServerCipherSuites != configs[i-1].PreferServerCipherSuites {
return nil, fmt.Errorf("cannot both PreferServerCipherSuites and not prefer them")
}
config.PreferServerCipherSuites = cfg.PreferServerCipherSuites
// Union curves
for _, curv := range cfg.CurvePreferences {
if _, ok := curvesAdded[curv]; !ok {
curvesAdded[curv] = struct{}{}
config.CurvePreferences = append(config.CurvePreferences, curv)
}
}
// Go with the widest range of protocol versions
if config.MinVersion == 0 || cfg.ProtocolMinVersion < config.MinVersion {
config.MinVersion = cfg.ProtocolMinVersion
}
if cfg.ProtocolMaxVersion > config.MaxVersion {
config.MaxVersion = cfg.ProtocolMaxVersion
}
// Go with the strictest ClientAuth type
if cfg.ClientAuth > config.ClientAuth {
config.ClientAuth = cfg.ClientAuth
}
}
// Is TLS disabled? If so, we're done here.
// By now, we know that all configs agree
// whether it is or not, so we can just look
// at the first one.
if len(configs) == 0 || !configs[0].Enabled {
return nil, nil
}
// Default cipher suites
if len(config.CipherSuites) == 0 {
config.CipherSuites = defaultCiphers
}
// For security, ensure TLS_FALLBACK_SCSV is always included first
if len(config.CipherSuites) == 0 || config.CipherSuites[0] != tls.TLS_FALLBACK_SCSV {
config.CipherSuites = append([]uint16{tls.TLS_FALLBACK_SCSV}, config.CipherSuites...)
}
// Set up client authentication if enabled
if config.ClientAuth != tls.NoClientCert {
pool := x509.NewCertPool()
clientCertsAdded := make(map[string]struct{})
for _, cfg := range configs {
for _, caFile := range cfg.ClientCerts {
// don't add cert to pool more than once
if _, ok := clientCertsAdded[caFile]; ok {
continue
}
clientCertsAdded[caFile] = struct{}{}
// Any client with a certificate from this CA will be allowed to connect
caCrt, err := ioutil.ReadFile(caFile)
if err != nil {
return nil, err
}
if !pool.AppendCertsFromPEM(caCrt) {
return nil, fmt.Errorf("error loading client certificate '%s': no certificates were successfully parsed", caFile)
}
}
}
config.ClientCAs = pool
}
// Associate the GetCertificate callback, or almost nothing we just did will work
config.GetCertificate = configMap.GetCertificate
return config, nil
}