Decouple request and response via WebSocket

active.de-DE.toml

@@ -14,6 +14,14 @@ other = "Dein Schlüsselmaterial ist bereit zum Herunterladen. Die herunterladba
 hash = "sha1-a479c9c34e878d07b4d67a73a48f432ad7dc53c8"
 other = "Herunterladen"
 
+["JavaScript.Certificate.Received"]
+hash = "sha1-217622c21b50fcfb864802155080be482c285456"
+other = "Zertifikat von der CA erhalten"
+
+["JavaScript.Certificate.Waiting"]
+hash = "sha1-0a528daa78d850d2c9360cdec82f6f849ffb6bcf"
+other = "Warte auf Zertifikat ..."
+
 ["JavaScript.KeyGen.Generated"]
 hash = "sha1-34cdfcdc837e3fc052733a3588cc3923b793103e"
 other = "Schlüssel in __seconds__ Sekunden erzeugt"

active.en-US.toml

@@ -14,6 +14,14 @@ other = "Your key material is ready for download. The downloadable file contains
 hash = "sha1-a479c9c34e878d07b4d67a73a48f432ad7dc53c8"
 other = "Download"
 
+["JavaScript.Certificate.Received"]
+hash = "sha1-217622c21b50fcfb864802155080be482c285456"
+other = "received certificate from CA"
+
+["JavaScript.Certificate.Waiting"]
+hash = "sha1-0a528daa78d850d2c9360cdec82f6f849ffb6bcf"
+other = "waiting for certificate ..."
+
 ["JavaScript.KeyGen.Generated"]
 hash = "sha1-34cdfcdc837e3fc052733a3588cc3923b793103e"
 other = "key generated in __seconds__ seconds"

active.en.toml

@@ -2,6 +2,8 @@ CSRButtonLabel = "Generate signing request"
 CSRGenTitle = "CSR generation in browser"
 DownloadDescription = "Your key material is ready for download. The downloadable file contains your private key and your certificate encrypted with your password. You can now use the file to install your certificate in your browser or other applications."
 DownloadLabel = "Download"
+"JavaScript.Certificate.Received" = "received certificate from CA"
+"JavaScript.Certificate.Waiting" = "waiting for certificate ..."
 "JavaScript.KeyGen.Generated" = "key generated in __seconds__ seconds"
 "JavaScript.KeyGen.Running" = "key generation running for __seconds__ seconds"
 "JavaScript.KeyGen.Started" = "started key generation"

go.mod

@@ -4,6 +4,10 @@ go 1.13
 
 require (
 	github.com/BurntSushi/toml v0.3.1
+	github.com/gobwas/httphead v0.1.0 // indirect
+	github.com/gobwas/pool v0.2.1 // indirect
+	github.com/gobwas/ws v1.0.4
+	github.com/google/uuid v1.1.2
 	github.com/gorilla/csrf v1.7.0
 	github.com/nicksnyder/go-i18n/v2 v2.1.1
 	github.com/sirupsen/logrus v1.7.0

go.sum

@@ -2,6 +2,14 @@ github.com/BurntSushi/toml v0.3.1 h1:WXkYYl6Yr3qBf1K79EBnL4mak0OimBfB0XUf9Vl28OQ
 github.com/BurntSushi/toml v0.3.1/go.mod h1:xHWCNGjB5oqiDr8zfno3MHue2Ht5sIBksp03qcyfWMU=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/gobwas/httphead v0.1.0 h1:exrUm0f4YX0L7EBwZHuCF4GDp8aJfVeBrlLQrs6NqWU=
+github.com/gobwas/httphead v0.1.0/go.mod h1:O/RXo79gxV8G+RqlR/otEwx4Q36zl9rqC5u12GKvMCM=
+github.com/gobwas/pool v0.2.1 h1:xfeeEhW7pwmX8nuLVlqbzVc7udMDrwetjEv+TZIz1og=
+github.com/gobwas/pool v0.2.1/go.mod h1:q8bcK0KcYlCgd9e7WYLm9LpyS+YeLd8JVDW6WezmKEw=
+github.com/gobwas/ws v1.0.4 h1:5eXU1CZhpQdq5kXbKb+sECH5Ia5KiO6CYzIzdlVx6Bs=
+github.com/gobwas/ws v1.0.4/go.mod h1:szmBTxLgaFppYjEmNtny/v3w89xOydFnnZMcgRRu/EM=
+github.com/google/uuid v1.1.2 h1:EVhdT+1Kseyi1/pUmXKaFxYsDNy9RQYkMWRH68J/W7Y=
+github.com/google/uuid v1.1.2/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
 github.com/gorilla/csrf v1.7.0 h1:mMPjV5/3Zd460xCavIkppUdvnl5fPXMpv2uz2Zyg7/Y=
 github.com/gorilla/csrf v1.7.0/go.mod h1:+a/4tCmqhG6/w4oafeAZ9pEa3/NZOWYVbD9fV0FwIQA=
 github.com/gorilla/securecookie v1.1.1 h1:miw7JPhV+b/lAHSXz4qd/nN9jRiAFV5FwjeKyCS8BvQ=

handlers/index.go

@@ -18,6 +18,15 @@ func NewIndexHandler(bundle *i18n.Bundle) *IndexHandler {
 }
 
 func (i *IndexHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	if r.Method != "GET" {
+		http.Error(w, http.StatusText(http.StatusMethodNotAllowed), http.StatusMethodNotAllowed)
+		return
+	}
+	if r.URL.Path != "/" {
+		http.Error(w, http.StatusText(http.StatusNotFound), http.StatusNotFound)
+		return
+	}
+
 	localizer := i18n.NewLocalizer(i.bundle, r.Header.Get("Accept-Language"))
 	csrGenTitle := localizer.MustLocalize(&i18n.LocalizeConfig{DefaultMessage: &i18n.Message{
 		ID:    "CSRGenTitle",

handlers/jslocales.go

@@ -32,6 +32,10 @@ func (j *JSLocalesHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 			Running   string `json:"running"`
 			Generated string `json:"generated"`
 		} `json:"keygen"`
+		Certificate struct {
+			Waiting  string `json:"waiting"`
+			Received string `json:"received"`
+		} `json:"certificate"`
 	}
 
 	translations := &translationData{}
@@ -47,6 +51,14 @@ func (j *JSLocalesHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 		ID:    "JavaScript.KeyGen.Generated",
 		Other: "key generated in __seconds__ seconds",
 	}})
+	translations.Certificate.Waiting = localizer.MustLocalize(&i18n.LocalizeConfig{DefaultMessage: &i18n.Message{
+		ID:    "JavaScript.Certificate.Waiting",
+		Other: "waiting for certificate ...",
+	}})
+	translations.Certificate.Received = localizer.MustLocalize(&i18n.LocalizeConfig{DefaultMessage: &i18n.Message{
+		ID:    "JavaScript.Certificate.Received",
+		Other: "received certificate from CA",
+	}})
 
 	encoder := json.NewEncoder(w)
 	if err := encoder.Encode(translations); err != nil {

handlers/registry.go

@@ -0,0 +1,172 @@
+package handlers
+
+import (
+	"bytes"
+	"crypto/x509"
+	"encoding/pem"
+	"errors"
+	"fmt"
+	"io/ioutil"
+	"os"
+	"os/exec"
+	"time"
+
+	"github.com/google/uuid"
+	log "github.com/sirupsen/logrus"
+)
+
+type SigningRequestRegistry struct {
+	caCertificates []*x509.Certificate
+	caChainMap     map[string][]string
+	requests       map[string]chan *responseData
+}
+
+func NewSigningRequestRegistry(caCertificates []*x509.Certificate) *SigningRequestRegistry {
+	return &SigningRequestRegistry{
+		caCertificates: caCertificates,
+		caChainMap:     make(map[string][]string),
+		requests:       make(map[string]chan *responseData),
+	}
+}
+
+func (registry *SigningRequestRegistry) AddSigningRequest(request *requestData) (string, error) {
+	requestUuid, err := uuid.NewRandom()
+	if err != nil {
+		return "", err
+	}
+	go func() {
+		responseChannel := make(chan *responseData, 1)
+		registry.requests[requestUuid.String()] = responseChannel
+		registry.signCertificate(responseChannel, request)
+	}()
+	return requestUuid.String(), nil
+}
+
+func (registry *SigningRequestRegistry) signCertificate(channel chan *responseData, request *requestData) {
+	responseData, err := registry.sign(request)
+	if err != nil {
+		log.Error(err)
+		close(channel)
+		return
+	}
+	channel <- responseData
+}
+
+func (registry *SigningRequestRegistry) sign(request *requestData) (response *responseData, err error) {
+	log.Debugf("received CSR for %s:\n\n%s", request.CommonName, request.Csr)
+	subjectDN := fmt.Sprintf("/CN=%s", request.CommonName)
+	var csrFile *os.File
+	if csrFile, err = ioutil.TempFile("", "*.csr.pem"); err != nil {
+		log.Errorf("could not open temporary file: %s", err)
+		return
+	}
+	if _, err = csrFile.Write([]byte(request.Csr)); err != nil {
+		log.Errorf("could not write CSR to file: %s", err)
+		return
+	}
+	if err = csrFile.Close(); err != nil {
+		log.Errorf("could not close CSR file: %s", err)
+		return
+	}
+	defer func(file *os.File) {
+		err = os.Remove(file.Name())
+		if err != nil {
+			log.Errorf("could not remove temporary file: %s", err)
+		}
+	}(csrFile)
+
+	// simulate a delay during certificate creation
+	time.Sleep(5 * time.Second)
+
+	opensslCommand := exec.Command(
+		"openssl", "ca", "-config", "ca.cnf",
+		"-policy", "policy_match", "-extensions", "client_ext",
+		"-batch", "-subj", subjectDN, "-utf8", "-rand_serial", "-in", "in.pem")
+	var out, cmdErr bytes.Buffer
+	opensslCommand.Stdout = &out
+	opensslCommand.Stderr = &cmdErr
+	err = opensslCommand.Run()
+	if err != nil {
+		log.Error(err)
+		log.Error(cmdErr.String())
+		return
+	}
+
+	var block *pem.Block
+	if block, _ = pem.Decode(out.Bytes()); block == nil {
+		err = fmt.Errorf("could not decode pem")
+		return
+	}
+	var certificate *x509.Certificate
+	if certificate, err = x509.ParseCertificate(block.Bytes); err != nil {
+		return
+	}
+
+	var caChain []string
+	if caChain, err = registry.getCAChain(certificate); err != nil {
+		return
+	}
+
+	response = &responseData{
+		Certificate: string(pem.EncodeToMemory(&pem.Block{
+			Type:  "CERTIFICATE",
+			Bytes: certificate.Raw,
+		})),
+		CAChain: caChain,
+	}
+	return
+}
+
+func (registry *SigningRequestRegistry) GetResponseChannel(requestUuid string) (chan *responseData, error) {
+	if responseChannel, exists := registry.requests[requestUuid]; exists {
+		delete(registry.requests, requestUuid)
+		return responseChannel, nil
+	} else {
+		return nil, errors.New("no request found")
+	}
+}
+
+func (registry *SigningRequestRegistry) getCAChain(certificate *x509.Certificate) ([]string, error) {
+	issuerString := string(certificate.RawIssuer)
+
+	if value, exists := registry.caChainMap[issuerString]; exists {
+		return value, nil
+	}
+
+	result := make([]string, 0)
+
+	appendCert := func(cert *x509.Certificate) {
+		result = append(
+			result,
+			string(pem.EncodeToMemory(&pem.Block{Bytes: cert.Raw, Type: "CERTIFICATE"})))
+		log.Debugf("added %s to cachain", result[len(result)-1])
+	}
+
+	var previous *x509.Certificate
+	var count = 0
+	for {
+		if len(registry.caCertificates) == 0 {
+			return nil, errors.New("no CA certificates loaded")
+		}
+		if count > len(registry.caCertificates) {
+			return nil, errors.New("could not construct certificate chain")
+		}
+		for _, caCert := range registry.caCertificates {
+			if previous == nil {
+				if bytes.Equal(caCert.RawSubject, certificate.RawIssuer) {
+					previous = caCert
+					appendCert(caCert)
+				}
+			} else if bytes.Equal(previous.RawSubject, previous.RawIssuer) {
+				registry.caChainMap[issuerString] = result
+				return result, nil
+			} else if bytes.Equal(caCert.RawSubject, previous.RawIssuer) {
+				previous = caCert
+				appendCert(caCert)
+			} else {
+				log.Debugf("skipped certificate %s", caCert.Subject)
+			}
+		}
+		count++
+	}
+}

handlers/signing.go

@@ -1,83 +1,18 @@
 package handlers
 
 import (
-	"bytes"
-	"crypto/x509"
 	"encoding/json"
-	"encoding/pem"
-	"errors"
-	"fmt"
-	"io/ioutil"
 	"net/http"
-	"os"
-	"os/exec"
 
 	log "github.com/sirupsen/logrus"
 )
 
 type CertificateSigningHandler struct {
-	caCertificates []*x509.Certificate
+	requestRegistry *SigningRequestRegistry
-	caChainMap     map[string][]string
 }
 
-func NewCertificateSigningHandler(caCertificates []*x509.Certificate) *CertificateSigningHandler {
+func NewCertificateSigningHandler(requestRegistry *SigningRequestRegistry) *CertificateSigningHandler {
-	return &CertificateSigningHandler{caCertificates: caCertificates, caChainMap: make(map[string][]string)}
+	return &CertificateSigningHandler{requestRegistry: requestRegistry}
-}
-
-func (h *CertificateSigningHandler) sign(csrPem string, commonName string) (certPem string, caChain []string, err error) {
-	log.Printf("received CSR for %s:\n\n%s", commonName, csrPem)
-	subjectDN := fmt.Sprintf("/CN=%s", commonName)
-	var csrFile *os.File
-	if csrFile, err = ioutil.TempFile("", "*.csr.pem"); err != nil {
-		log.Errorf("could not open temporary file: %s", err)
-		return
-	}
-	if _, err = csrFile.Write([]byte(csrPem)); err != nil {
-		log.Errorf("could not write CSR to file: %s", err)
-		return
-	}
-	if err = csrFile.Close(); err != nil {
-		log.Errorf("could not close CSR file: %s", err)
-		return
-	}
-	defer func(file *os.File) {
-		err = os.Remove(file.Name())
-		if err != nil {
-			log.Errorf("could not remove temporary file: %s", err)
-		}
-	}(csrFile)
-
-	opensslCommand := exec.Command(
-		"openssl", "ca", "-config", "ca.cnf",
-		"-policy", "policy_match", "-extensions", "client_ext",
-		"-batch", "-subj", subjectDN, "-utf8", "-rand_serial", "-in", "in.pem")
-	var out, cmdErr bytes.Buffer
-	opensslCommand.Stdout = &out
-	opensslCommand.Stderr = &cmdErr
-	err = opensslCommand.Run()
-	if err != nil {
-		log.Print(err)
-		log.Print(cmdErr.String())
-		return
-	}
-
-	var block *pem.Block
-	if block, _ = pem.Decode(out.Bytes()); block == nil {
-		err = fmt.Errorf("could not decode pem")
-		return
-	}
-	var certificate *x509.Certificate
-	if certificate, err = x509.ParseCertificate(block.Bytes); err != nil {
-		return
-	}
-
-	certPem = string(pem.EncodeToMemory(&pem.Block{
-		Type:  "CERTIFICATE",
-		Bytes: certificate.Raw,
-	}))
-
-	caChain, err = h.getCAChain(certificate)
-	return
 }
 
 func (h *CertificateSigningHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
@@ -91,26 +26,27 @@ func (h *CertificateSigningHandler) ServeHTTP(w http.ResponseWriter, r *http.Req
 	}
 	var err error
 	var requestBody requestData
-	var responseData responseData
 
 	if err = json.NewDecoder(r.Body).Decode(&requestBody); err != nil {
-		log.Print(err)
+		log.Error(err)
 		http.Error(w, err.Error(), http.StatusBadRequest)
 		return
 	}
 
-	responseData.Certificate, responseData.CAChain, err = h.sign(requestBody.Csr, requestBody.CommonName)
+	type acceptedResponse struct {
+		RequestId string `json:"request_id"`
+	}
+
+	taskUuid, err := h.requestRegistry.AddSigningRequest(&requestBody)
 	if err != nil {
-		http.Error(w, "Could not sign certificate", http.StatusInternalServerError)
+		log.Error(err)
+		http.Error(w, http.StatusText(http.StatusInternalServerError), http.StatusInternalServerError)
 		return
 	}
 
-	var jsonBytes []byte
+	w.WriteHeader(http.StatusAccepted)
-	if jsonBytes, err = json.Marshal(&responseData); err != nil {
+	response := &acceptedResponse{RequestId: taskUuid}
-		log.Print(err)
+	if err = json.NewEncoder(w).Encode(response); err != nil {
-	}
-
-	if _, err = w.Write(jsonBytes); err != nil {
 		log.Print(err)
 	}
 }
@@ -124,48 +60,3 @@ type responseData struct {
 	Certificate string   `json:"certificate"`
 	CAChain     []string `json:"ca_chain"`
 }
-
-func (h *CertificateSigningHandler) getCAChain(certificate *x509.Certificate) ([]string, error) {
-	issuerString := string(certificate.RawIssuer)
-
-	if value, exists := h.caChainMap[issuerString]; exists {
-		return value, nil
-	}
-
-	result := make([]string, 0)
-
-	appendCert := func(cert *x509.Certificate) {
-		result = append(
-			result,
-			string(pem.EncodeToMemory(&pem.Block{Bytes: cert.Raw, Type: "CERTIFICATE"})))
-		log.Debugf("added %s to cachain", result[len(result)-1])
-	}
-
-	var previous *x509.Certificate
-	var count = 0
-	for {
-		if len(h.caCertificates) == 0 {
-			return nil, errors.New("no CA certificates loaded")
-		}
-		if count > len(h.caCertificates) {
-			return nil, errors.New("could not construct certificate chain")
-		}
-		for _, caCert := range h.caCertificates {
-			if previous == nil {
-				if bytes.Equal(caCert.RawSubject, certificate.RawIssuer) {
-					previous = caCert
-					appendCert(caCert)
-				}
-			} else if bytes.Equal(previous.RawSubject, previous.RawIssuer) {
-				h.caChainMap[issuerString] = result
-				return result, nil
-			} else if bytes.Equal(caCert.RawSubject, previous.RawIssuer) {
-				previous = caCert
-				appendCert(caCert)
-			} else {
-				log.Debugf("skipped certificate %s", caCert.Subject)
-			}
-		}
-		count++
-	}
-}

handlers/websocket.go

@@ -0,0 +1,79 @@
+package handlers
+
+import (
+	"encoding/json"
+	"net/http"
+
+	"github.com/gobwas/ws"
+	"github.com/gobwas/ws/wsutil"
+	log "github.com/sirupsen/logrus"
+)
+
+type WebSocketHandler struct {
+	requestRegistry *SigningRequestRegistry
+}
+
+func NewWebSocketHandler(registry *SigningRequestRegistry) *WebSocketHandler {
+	return &WebSocketHandler{requestRegistry: registry}
+}
+
+func (w *WebSocketHandler) ServeHTTP(writer http.ResponseWriter, request *http.Request) {
+	conn, _, _, err := ws.UpgradeHTTP(request, writer)
+	if err != nil {
+		http.Error(writer, http.StatusText(http.StatusInternalServerError), http.StatusInternalServerError)
+		return
+	}
+
+	go func() {
+		defer func() { _ = conn.Close() }()
+
+		var (
+			reader      = wsutil.NewReader(conn, ws.StateServerSide)
+			writer      = wsutil.NewWriter(conn, ws.StateServerSide, ws.OpText)
+			jsonDecoder = json.NewDecoder(reader)
+			jsonEncoder = json.NewEncoder(writer)
+		)
+
+		for {
+			header, err := reader.NextFrame()
+			if err != nil {
+				log.Error(err)
+				break
+			}
+			if header.OpCode == ws.OpClose {
+				log.Debug("channel closed")
+				break
+			}
+
+			type requestType struct {
+				RequestId string `json:"request_id"`
+			}
+
+			request := &requestType{}
+			err = jsonDecoder.Decode(request)
+			if err != nil {
+				log.Error(err)
+				break
+			}
+
+			channel, err := w.requestRegistry.GetResponseChannel(request.RequestId)
+			if err != nil {
+				log.Error(err)
+				break
+			}
+
+			var response *responseData
+			response = <-channel
+			if err = jsonEncoder.Encode(response); err != nil {
+				log.Error(err)
+				break
+			}
+			close(channel)
+
+			if err = writer.Flush(); err != nil {
+				log.Error(err)
+				break
+			}
+		}
+	}()
+}

main.go

@@ -41,12 +41,14 @@ func main() {
 
 	csrfKey := initCSRFKey()
 
-	mux.Handle("/sign/", handlers.NewCertificateSigningHandler(loadCACertificates()))
+	signingRequestRegistry := handlers.NewSigningRequestRegistry(loadCACertificates())
+	mux.Handle("/sign/", handlers.NewCertificateSigningHandler(signingRequestRegistry))
 	mux.Handle("/", handlers.NewIndexHandler(bundle))
 	fileServer := http.FileServer(http.Dir("./public"))
 	mux.Handle("/css/", fileServer)
 	mux.Handle("/js/", fileServer)
 	mux.Handle("/locales/", handlers.NewJSLocalesHandler(bundle))
+	mux.Handle("/ws/", handlers.NewWebSocketHandler(signingRequestRegistry))
 	server := http.Server{
 		Addr:              ":8000",
 		Handler:           csrf.Protect(csrfKey, csrf.FieldName("csrfToken"), csrf.RequestHeader("X-CSRF-Token"))(mux),

templates/index.html

@@ -148,8 +148,34 @@
                         document.getElementById("csr").innerHTML = csrPem;
                         progressBar.style.width = "75%";
                         progressBar.setAttribute("aria-valuenow", "3");
+                        progressBar.classList.add('progress-bar-striped', 'progress-bar-animated');
+                        progressBar.innerHTML = i18n.t('keygen.generated', {seconds: seconds}) + ', ' + i18n.t('certificate.waiting');
                         postData("/sign/", {"csr": csrPem, "commonName": subject}, csrfToken)
                             .then(data => {
+                                const request_id = data["request_id"]
+                                const webSocket = new WebSocket(
+                                    "wss://" + window.location.toString().substring(
+                                    "https://".length
+                                    ).split("/")[0] + "/ws/")
+                                webSocket.onopen = function () {
+                                    webSocket.send(JSON.stringify({"request_id": request_id}))
+                                }
+                                webSocket.onmessage = function (event) {
+                                    handleCertificateResponse(JSON.parse(event.data));
+                                }
+                                webSocket.onclose = function (event) {
+                                    if (event.wasClean) {
+                                        console.debug("websocket closed cleanly");
+                                    } else {
+                                        console.error("websocket connection died");
+                                    }
+                                }
+                                webSocket.onerror = function (error) {
+                                    console.error(error.message);
+                                }
+                            });
+
+                        function handleCertificateResponse(data) {
                             document.getElementById("crt").innerHTML = data["certificate"];
                             let certificates = []
                             certificates.push(forge.pki.certificateFromPem(data["certificate"]));
@@ -171,9 +197,11 @@
                             downloadLink.setAttribute('href', 'data:application/x-pkcs12;base64,' + p12B64);
 
                             document.getElementById('download-wrapper').classList.remove("d-none");
+                            progressBar.classList.remove("progress-bar-animated", 'progress-bar-striped');
                             progressBar.style.width = "100%";
+                            progressBar.innerHTML = i18n.t('keygen.generated', {seconds: seconds}) + ', ' + i18n.t('certificate.received');
                             progressBar.setAttribute("aria-valuenow", "4");
-                            });
+                        }
                     }
                 }
             }