support mutual TLS authentication

cmd/gost/cfg.go

@@ -44,8 +44,9 @@ var (
 	defaultKeyFile  = "key.pem"
 )
 
-// Load the certificate from cert and key files, will use the default certificate if the provided info are invalid.
-func tlsConfig(certFile, keyFile string) (*tls.Config, error) {
+// Load the certificate from cert & key files and optional client CA file,
+// will use the default certificate if the provided info are invalid.
+func tlsConfig(certFile, keyFile, caFile string) (*tls.Config, error) {
 	if certFile == "" || keyFile == "" {
 		certFile, keyFile = defaultCertFile, defaultKeyFile
 	}
@@ -54,7 +55,15 @@ func tlsConfig(certFile, keyFile string) (*tls.Config, error) {
 	if err != nil {
 		return nil, err
 	}
-	return &tls.Config{Certificates: []tls.Certificate{cert}}, nil
+
+	cfg := &tls.Config{Certificates: []tls.Certificate{cert}}
+
+	if pool, _ := loadCA(caFile); pool != nil {
+		cfg.ClientCAs = pool
+		cfg.ClientAuth = tls.RequireAndVerifyClientCert
+	}
+
+	return cfg, nil
 }
 
 func loadCA(caFile string) (cp *x509.CertPool, err error) {

cmd/gost/main.go

@@ -67,7 +67,7 @@ func main() {
 	}
 
 	// NOTE: as of 2.6, you can use custom cert/key files to initialize the default certificate.
-	tlsConfig, err := tlsConfig(defaultCertFile, defaultKeyFile)
+	tlsConfig, err := tlsConfig(defaultCertFile, defaultKeyFile, "")
 	if err != nil {
 		// generate random self-signed certificate.
 		cert, err := gost.GenCertificate()

cmd/gost/route.go

@@ -128,6 +128,10 @@ func parseChainNode(ns string) (nodes []gost.Node, err error) {
 		InsecureSkipVerify: !node.GetBool("secure"),
 		RootCAs:            rootCAs,
 	}
+	if cert, err := tls.LoadX509KeyPair(node.Get("cert"), node.Get("key")); err == nil {
+		tlsCfg.Certificates = []tls.Certificate{cert}
+	}
+
 	wsOpts := &gost.WSOptions{}
 	wsOpts.EnableCompression = node.GetBool("compression")
 	wsOpts.ReadBufferSize = node.GetInt("rbuf")
@@ -343,7 +347,7 @@ func (r *route) GenRouters() ([]router, error) {
 			}
 		}
 		certFile, keyFile := node.Get("cert"), node.Get("key")
-		tlsCfg, err := tlsConfig(certFile, keyFile)
+		tlsCfg, err := tlsConfig(certFile, keyFile, node.Get("ca"))
 		if err != nil && certFile != "" && keyFile != "" {
 			return nil, err
 		}