156 lines
3.5 KiB
Go
156 lines
3.5 KiB
Go
package main
|
|
|
|
import (
|
|
"context"
|
|
"crypto/tls"
|
|
"crypto/x509"
|
|
"errors"
|
|
"fmt"
|
|
"io/ioutil"
|
|
"log"
|
|
"os"
|
|
"sync"
|
|
"time"
|
|
|
|
"google.golang.org/grpc"
|
|
"google.golang.org/grpc/credentials"
|
|
|
|
"github.com/smallstep/certificates/autocert/examples/hello-mtls/go-grpc/hello"
|
|
)
|
|
|
|
const (
|
|
autocertFile = "/var/run/autocert.step.sm/site.crt"
|
|
autocertKey = "/var/run/autocert.step.sm/site.key"
|
|
autocertRoot = "/var/run/autocert.step.sm/root.crt"
|
|
requestFrequency = 5 * time.Second
|
|
tickFrequency = 15 * time.Second
|
|
)
|
|
|
|
// Uses techniques from https://diogomonica.com/2017/01/11/hitless-tls-certificate-rotation-in-go/
|
|
// to automatically rotate certificates when they're renewed.
|
|
|
|
type rotator struct {
|
|
sync.RWMutex
|
|
certificate *tls.Certificate
|
|
}
|
|
|
|
func (r *rotator) getClientCertificate(cri *tls.CertificateRequestInfo) (*tls.Certificate, error) {
|
|
r.RLock()
|
|
defer r.RUnlock()
|
|
return r.certificate, nil
|
|
}
|
|
|
|
func (r *rotator) loadCertificate(certFile, keyFile string) error {
|
|
r.Lock()
|
|
defer r.Unlock()
|
|
|
|
c, err := tls.LoadX509KeyPair(certFile, keyFile)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
|
|
r.certificate = &c
|
|
|
|
return nil
|
|
}
|
|
|
|
func loadRootCertPool() (*x509.CertPool, error) {
|
|
root, err := ioutil.ReadFile(autocertRoot)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
pool := x509.NewCertPool()
|
|
if ok := pool.AppendCertsFromPEM(root); !ok {
|
|
return nil, errors.New("Missing or invalid root certificate")
|
|
}
|
|
|
|
return pool, nil
|
|
}
|
|
|
|
func sayHello(c hello.GreeterClient) error {
|
|
ctx, cancel := context.WithTimeout(context.Background(), time.Second)
|
|
defer cancel()
|
|
|
|
r, err := c.SayHello(ctx, &hello.HelloRequest{Name: "world"})
|
|
if err != nil {
|
|
return err
|
|
}
|
|
log.Printf("Greeting: %s", r.Message)
|
|
return nil
|
|
}
|
|
|
|
func sayHelloAgain(c hello.GreeterClient) error {
|
|
ctx, cancel := context.WithTimeout(context.Background(), time.Second)
|
|
defer cancel()
|
|
|
|
r, err := c.SayHelloAgain(ctx, &hello.HelloRequest{Name: "world"})
|
|
if err != nil {
|
|
return err
|
|
}
|
|
log.Printf("Greeting: %s", r.Message)
|
|
return nil
|
|
}
|
|
|
|
func main() {
|
|
// Read the root certificate for our CA from disk
|
|
roots, err := loadRootCertPool()
|
|
if err != nil {
|
|
log.Fatal(err)
|
|
}
|
|
|
|
// Load certificate
|
|
r := &rotator{}
|
|
if err := r.loadCertificate(autocertFile, autocertKey); err != nil {
|
|
log.Fatal("error loading certificate and key", err)
|
|
}
|
|
tlsConfig := &tls.Config{
|
|
RootCAs: roots,
|
|
MinVersion: tls.VersionTLS12,
|
|
CurvePreferences: []tls.CurveID{tls.CurveP521, tls.CurveP384, tls.CurveP256},
|
|
CipherSuites: []uint16{
|
|
tls.TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305,
|
|
tls.TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256,
|
|
},
|
|
GetClientCertificate: r.getClientCertificate,
|
|
}
|
|
|
|
// Schedule periodic re-load of certificate
|
|
done := make(chan struct{})
|
|
go func() {
|
|
ticker := time.NewTicker(tickFrequency)
|
|
defer ticker.Stop()
|
|
for {
|
|
select {
|
|
case <-ticker.C:
|
|
fmt.Println("Checking for new certificate...")
|
|
err := r.loadCertificate(autocertFile, autocertKey)
|
|
if err != nil {
|
|
log.Println("Error loading certificate and key", err)
|
|
}
|
|
case <-done:
|
|
return
|
|
}
|
|
}
|
|
}()
|
|
defer close(done)
|
|
|
|
// Set up a connection to the server.
|
|
address := os.Getenv("HELLO_MTLS_URL")
|
|
conn, err := grpc.Dial(address, grpc.WithTransportCredentials(credentials.NewTLS(tlsConfig)))
|
|
if err != nil {
|
|
log.Fatalf("did not connect: %v", err)
|
|
}
|
|
defer conn.Close()
|
|
client := hello.NewGreeterClient(conn)
|
|
|
|
for {
|
|
if err := sayHello(client); err != nil {
|
|
log.Fatalf("could not greet: %v", err)
|
|
}
|
|
if err := sayHelloAgain(client); err != nil {
|
|
log.Fatalf("could not greet: %v", err)
|
|
}
|
|
time.Sleep(requestFrequency)
|
|
}
|
|
}
|