Broken TLS + AddService for go-rpcgen

add.go

ackage main

import (
	"flag"
	"log"
	"net"
	"crypto/rand"
	"crypto/tls"
	"crypto/x509"
	"./addservice"
)

var (
	addr    = flag.String("addr", ":9999", "RPC Server address (transient)")
	message = flag.String("message", "test", "Test echo message")
)

// Echo is the type which will implement the echoservice.EchoService interface
// and can be called remotely.  In this case, it does not have any state, but
// it could.
type Add struct{}

// Echo is the function that can be called remotely.  Note that this can be
// called concurrently, so if the Echo structure did have internal state,
// it should be designed for concurrent access.
func (Add) Add(in *addservice.AddMessage, out *addservice.SumMessage) error {
	log.Printf("server: x=%d", *in.X)
	log.Printf("server: y=%d", *in.Y)
	out.Z = new(int32)
	*out.Z = *in.X + *in.Y
	log.Printf("server: zz=%d", *out.Z)
	return nil
}

func handleClient(conn net.Conn) {
	defer conn.Close()
	tlscon, ok := conn.(*tls.Conn)
	if ok {
		log.Print("server: conn: type assert to TLS succeedded")
		err := tlscon.Handshake()
		if err != nil {
			log.Fatalf("server: handshake failed: %s", err)
		} else {
			log.Print("server: conn: Handshake completed")
		}
		state := tlscon.ConnectionState()
		log.Println("Server: client public key is:")
		for _, v := range state.PeerCertificates {
			log.Print(x509.MarshalPKIXPublicKey(v.PublicKey))
		}
		addservice.ServeAddService(conn,Add{})
	}
}

func serverTLSListen(service string) {
	cert, err := tls.LoadX509KeyPair("certs/server.pem", "certs/server.key")
	if err != nil {
		log.Fatalf("server: loadkeys: %s", err)
	}
	config := tls.Config{Certificates: []tls.Certificate{cert}, ClientAuth: tls.RequireAnyClientCert}
	config.Rand = rand.Reader
	listener, err := tls.Listen("tcp", service, &config)
	if err != nil {
		log.Fatalf("server: listen: %s", err)
	}
	log.Print("server: listening")
	for {
		conn, err := listener.Accept()
		if err != nil {
			log.Printf("server: accept: %s", err)
			break
		}
		log.Printf("server: accepted from %s", conn.RemoteAddr())
		go handleClient(conn)
	}
}

func main() {
	flag.Parse()
	serverTLSListen("0.0.0.0:8000")
}

addservice.proto

package addservice;

message add_message {
	required int32 x=1;
	required int32 y=2;
}

message sum_message {
	required int32 z=1;
}

service add_service {
  rpc add (add_message) returns (sum_message);
}

client.go

package main

import (
	"bufio"
	"crypto/tls"
	"crypto/x509"
	"flag"
	"fmt"
	"io"
	"log"
	"os"
	//	"github.com/kylelemons/go-rpcgen/examples/echo/echoservice"
	"../addservice"
)

var server = flag.String("server", "localhost:9999", "RPC server address")

func openTLSClient(ipPort string) (*tls.Conn, error) {
	cert, err := tls.LoadX509KeyPair("certs/client.pem", "certs/client.key")
	if err != nil {
		log.Fatalf("server: loadkeys: %s", err)
	}
	config := tls.Config{Certificates: []tls.Certificate{cert}, InsecureSkipVerify: true}
	conn, err := tls.Dial("tcp", ipPort, &config)
	if err != nil {
		log.Fatalf("client: dial: %s", err)
	}
	defer conn.Close()
	log.Println("client: connected to: ", conn.RemoteAddr())
	state := conn.ConnectionState()
	for _, v := range state.PeerCertificates {
		fmt.Println("Client: Server public key is:")
		fmt.Println(x509.MarshalPKIXPublicKey(v.PublicKey))
	}
	log.Println("client: handshake: ", state.HandshakeComplete)
	log.Println("client: mutual: ", state.NegotiatedProtocolIsMutual)

	return conn, err
}

func main() {

	var x int32
	var y int32
	conn, err := openTLSClient("127.0.0.1:8000")
	sum := addservice.NewAddServiceClient(conn)
	if err != nil {
		log.Fatalf("dial: %s", err)
	}

	lines := bufio.NewReader(os.Stdin)
	x = 2
	y = 3
	for {
		os.Stdout.WriteString("sending 2+3")
		os.Stdout.WriteString("> ")
		line, err := lines.ReadString('\n')
		if err != nil {
			if err == io.EOF {
				return
			}
			log.Fatalf("read: %s", err)
		}

		in := &addservice.AddMessage{X: &x, Y: &y}
		out := &addservice.SumMessage{}
		if err := sum.Add(in, out); err != nil {
			log.Fatalf("echo: %s", err)
		}
		if out.Z == nil {
			log.Fatalf("echo: no message returned")
		}
		os.Stdout.WriteString("< ")
		os.Stdout.WriteString(line)
		fmt.Println(*out.Z)
	}
}

makecert.sh

#!/bin/bash
# call this script with an email address (valid or not).
# like:
# ./makecert.sh [email protected]
mkdir certs
rm certs/*
echo "make server cert"
openssl req -new -nodes -x509 -out certs/server.pem -keyout certs/server.key -days 3650 -subj "/C=DE/ST=NRW/L=Earth/O=Random Company/OU=IT/CN=www.random.com/emailAddress=$1"
echo "make client cert"
openssl req -new -nodes -x509 -out certs/client.pem -keyout certs/client.key -days 3650 -subj "/C=DE/ST=NRW/L=Earth/O=Random Company/OU=IT/CN=www.random.com/emailAddress=$1"