Handle client certificate failures

boardvoting.go

@@ -26,6 +26,7 @@ import (
 	"embed"
 	"encoding/base64"
 	"encoding/pem"
+	"errors"
 	"flag"
 	"fmt"
 	"html/template"
@@ -674,9 +675,17 @@ func (h *directVoteHandler) Handle(w http.ResponseWriter, r *http.Request) {
 
 	switch r.Method {
 	case http.MethodPost:
+		clientCert, err := getPEMClientCert(r)
+		if err != nil {
+			log.Errorf("could not get client certificate from request: %v", err)
+			http.Error(w, http.StatusText(http.StatusInternalServerError), http.StatusInternalServerError)
+
+			return
+		}
+
 		voteResult := &Vote{
 			VoterID: voter.ID, Vote: vote, DecisionID: decision.ID, Voted: time.Now().UTC(),
-			Notes: fmt.Sprintf("Direct Vote\n\n%s", getPEMClientCert(r))}
+			Notes: fmt.Sprintf("Direct Vote\n\n%s", clientCert)}
 		if err := voteResult.Save(); err != nil {
 			log.Errorf("Problem saving vote: %v", err)
 			http.Error(w, "Problem saving vote", http.StatusInternalServerError)
@@ -719,16 +728,22 @@ type proxyVoteHandler struct {
 	authenticationRequiredHandler
 }
 
-func getPEMClientCert(r *http.Request) string {
-	clientCertPEM := bytes.NewBufferString("")
-	authenticatedCertificate := r.Context().Value(ctxAuthenticatedCert).(*x509.Certificate)
+func getPEMClientCert(r *http.Request) (string, error) {
+	cert := r.Context().Value(ctxAuthenticatedCert)
+
+	authenticatedCertificate, ok := cert.(*x509.Certificate)
+	if !ok {
+		return "", errors.New("could not handle certificate as x509.Certificate")
+	}
+
+	clientCertPEM := bytes.NewBuffer(make([]byte, 0))
 
 	err := pem.Encode(clientCertPEM, &pem.Block{Type: "CERTIFICATE", Bytes: authenticatedCertificate.Raw})
 	if err != nil {
-		log.Errorf("error encoding client certificate: %v", err)
+		return "", fmt.Errorf("error encoding client certificate: %w", err)
 	}
 
-	return clientCertPEM.String()
+	return clientCertPEM.String(), nil
 }
 
 func (h *proxyVoteHandler) Handle(w http.ResponseWriter, r *http.Request) {
@@ -788,11 +803,17 @@ func (h *proxyVoteHandler) Handle(w http.ResponseWriter, r *http.Request) {
 
 			renderTemplate(w, r, templates, templateContext)
 		} else {
+			clientCert, err := getPEMClientCert(r)
+			if err != nil {
+				log.Errorf("could not get client certificate information: %v", err)
+				http.Error(w, http.StatusText(http.StatusInternalServerError), http.StatusInternalServerError)
+
+				return
+			}
+
 			data.DecisionID = decision.ID
 			data.Voted = time.Now().UTC()
-			data.Notes = fmt.Sprintf(
-				"Proxy-Vote by %s\n\n%s\n\n%s",
-				proxy.Name, justification, getPEMClientCert(r))
+			data.Notes = fmt.Sprintf("Proxy-Vote by %s\n\n%s\n\n%s", proxy.Name, justification, clientCert)
 
 			if err := data.Save(); err != nil {
 				log.Errorf("Error saving vote: %s", err)