failed to complete security handshake on grpc?

I've already changed many times the port number on the server and client, but the server always get the incorrect port number.

when I execute the client the server will log this:
2017/05/07 15:06:07 grpc: Server.Serve failed to complete security handshake from "127.0.0.1:32763": remote error: tls: bad certificate
and on the client side, i got this:
2017/05/07 15:06:07 Failed to dial localhost:8070: connection error: desc = "transport: x509: certificate is not valid for any names, but wanted to match localhost:8070"; please retry.
rpc error: code = Internal desc = connection error: desc = "transport: x509: certificate is not valid for any names, but wanted to match localhost:8070"

I have this code for the server.go

func serve() {
addr := "localhost:8070"
crt, key := certificate.CreatePemKey()
certificate, err := tls.X509KeyPair(crt, key)
if err != nil {
fmt.Println(err)
}
certPool := x509.NewCertPool()
ca, err := ioutil.ReadFile("F:/GIAG3.crt")
if err != nil {
fmt.Println(err)
}
if ok := certPool.AppendCertsFromPEM(ca); !ok {
fmt.Println("unable to append certificate")
}
lis, err := net.Listen("tcp", addr)
if err != nil {
fmt.Println("could not list on %s: %s", addr, err)
}
// Create the TLS credentials
creds := credentials.NewTLS(&tls.Config{
ClientAuth:   tls.RequireAndVerifyClientCert,
Certificates: []tls.Certificate{certificate},
ClientCAs:    certPool,
})
srv := grpc.NewServer(grpc.Creds(creds))
pb.RegisterPingerServer(srv, &server{})
if err := srv.Serve(lis); err != nil {
fmt.Println("grpc serve error: %s", err)
}
}

and this is for the client.go

func testDial2() {
addr := "localhost:8070"
crt, key := certificate.CreatePemKey()
certificate, err := tls.X509KeyPair(crt, key)
if err != nil {
fmt.Println(err)
}
certPool := x509.NewCertPool()
ca, err := ioutil.ReadFile("F:/GIAG3.crt")
if err != nil {
fmt.Println(err)
}
if ok := certPool.AppendCertsFromPEM(ca); !ok {
fmt.Println("unable to append certificate")
}
creds := credentials.NewTLS(&tls.Config{
ServerName:   addr,
Certificates: []tls.Certificate{certificate},
RootCAs:      certPool,
})
conn, err := grpc.Dial(addr, grpc.WithTransportCredentials(creds))
if err != nil {
fmt.Println(err)
}
defer conn.Close()
c := pb.NewPingerClient(conn)
r, err := c.Ping(context.Background(), &pb.Payload{Message: "Ping"})
if err != nil {
fmt.Println(err)
}
log.Printf("%s", r.Message)
}

this is for the CreatePemKey, it is based on this example https://golang.org/src/crypto/tls/generate_cert.go

func publicKey(priv interface{}) interface{} {
switch k := priv.(type) {
case *rsa.PrivateKey:
return &k.PublicKey
case *ecdsa.PrivateKey:
return &k.PublicKey
default:
return nil
}
}
func pemBlockForKey(priv interface{}) *pem.Block {
switch k := priv.(type) {
case *rsa.PrivateKey:
return &pem.Block{Type: "RSA PRIVATE KEY", Bytes: x509.MarshalPKCS1PrivateKey(k)}
case *ecdsa.PrivateKey:
b, err := x509.MarshalECPrivateKey(k)
if err != nil {
fmt.Fprintf(os.Stderr, "Unable to marshal ECDSA private key: %v", err)
os.Exit(2)
}
return &pem.Block{Type: "EC PRIVATE KEY", Bytes: b}
default:
return nil
}
}
func CreatePemKey() (certpem, keypem []byte) {
priv, _ := rsa.GenerateKey(rand.Reader, 2048)
notBefore := time.Now()
notAfter := notBefore.AddDate(1, 0, 0)
serialNumberLimit := new(big.Int).Lsh(big.NewInt(1), 128)
serialNumber, _ := rand.Int(rand.Reader, serialNumberLimit)
template := x509.Certificate{
SerialNumber: serialNumber,
Subject: pkix.Name{
Organization: []string{"Acme Co"},
},
NotBefore:             notBefore,
NotAfter:              notAfter,
KeyUsage:              x509.KeyUsageKeyEncipherment | x509.KeyUsageDigitalSignature,
ExtKeyUsage:           []x509.ExtKeyUsage{x509.ExtKeyUsageServerAuth},
BasicConstraintsValid: true,
}
// template.IPAddresses = append(template.IPAddresses, net.ParseIP("localhost"))
template.IsCA = true
derbytes, _ := x509.CreateCertificate(rand.Reader, &template, &template, publicKey(priv), priv)
certpem = pem.EncodeToMemory(&pem.Block{Type: "CERTIFICATE", Bytes: derbytes})
keypem = pem.EncodeToMemory(pemBlockForKey(priv))
return certpem, keypem
}

BTW the GIAG3.crt is came from here https://pki.goog/

Please help me, thanks

If your server certificate doesn't have the domain definition and it's not signed by GIAG3 (like your example), you should add InsecureSkipVerify (this allow you skip the validation of the server name and the server certificate) in the client configuration, that will fix the issue with the invalid name.

<!-- language: go -->

creds := credentials.NewTLS(&tls.Config{
ServerName:   addr,
Certificates: []tls.Certificate{certificate},
RootCAs:      certPool,
InsecureSkipVerify: true,
})

But you'll have another problem, because the client is using a self-signed certificate, and the server required a certificate signed by GIAG3 for the authentication (tls.RequireAndVerifyClientCert), so you have some options with this,

• you use a certificate signed by GIAG3 for the client.
• reduce the authentication type to tls.RequireAnyClientCert, this allow you use any certificate at the moment of the auth (it could be or not signed by GIAG3), the client just need to use any certificate when it's connected.
• remove the client authentication with certificate.

If you found this log in journalctl -u docker:

mai 29 10:33:04 ca275nt dockerd[1523]: time="2019-05-29T10:33:04.454362399-03:00" level=warning msg="grpc: Server.Serve failed to complete security handshake from \"192.168.0.45:58392\": remote error: tls: bad certificate" module=grpc    

It can be related with docker swarm requests from another swarm cluster node host trying to connect to docker swarm master node with a invalid token.

You can discover the invalid cluster node hostname with:

nslookup 192.168.0.45                                                                                                                                          
45.0.168.192.in-addr.arpa       name = hostabc.domain.com.
45.0.168.192.in-addr.arpa       name = hostabc.
Authoritative answers can be found from:

By running a docker swarm leave on the reported host, resolve the issue.

I know it's not related with the main question, but I was searching for:
docker "grpc: Server.Serve failed to complete security handshake from" and this was the first question. then I think it's useful to put the troubleshooting here to save some time to others.