token-validator: add missing SSH challenge

token-validator/challenge.go

@@ -30,6 +30,10 @@ func noAccessRestriction(*Student, *http.Request) error {
 	return nil
 }
 
+func noAccess(*Student, *http.Request) error {
+	return errors.New("This challenge cannot be accessed this way. ")
+}
+
 func accessFrom(ip string) func(_ *Student, r *http.Request) error {
 	return func(_ *Student, r *http.Request) error {
 		if r.Header.Get("X-Forwarded-By") != ip {
@@ -243,6 +247,9 @@ func init() {
 		},
 
 		/* Last : SSH key, see ssh.go:156 in NewKey function */
+		Challenge{
+			Accessible: []func(*Student, *http.Request) error{noAccess},
+		},
 	}
 
 	router.GET("/challenges", apiHandler(getChallengeList))