fix dhparam generation

it cannot be created in default config creation time since it is
already run pre-VM snapshot time

src/provision.js

@@ -10,7 +10,6 @@ exports = module.exports = {
 const assert = require('assert'),
     backups = require('./backups.js'),
     backuptask = require('./backuptask.js'),
-    blobs = require('./blobs.js'),
     BoxError = require('./boxerror.js'),
     branding = require('./branding.js'),
     constants = require('./constants.js'),
@@ -18,6 +17,7 @@ const assert = require('assert'),
     debug = require('debug')('box:provision'),
     domains = require('./domains.js'),
     eventlog = require('./eventlog.js'),
+    fs = require('fs'),
     mail = require('./mail.js'),
     mounts = require('./mounts.js'),
     reverseProxy = require('./reverseproxy.js'),
@@ -25,6 +25,7 @@ const assert = require('assert'),
     semver = require('semver'),
     settings = require('./settings.js'),
     sysinfo = require('./sysinfo.js'),
+    paths = require('./paths.js'),
     users = require('./users.js'),
     tld = require('tldjs'),
     tokens = require('./tokens.js'),
@@ -50,6 +51,14 @@ function setProgress(task, message, callback) {
     if (callback) callback();
 }
 
+async function ensureDhparams() {
+    if (fs.existsSync(paths.DHPARAMS_FILE)) return;
+    debug('ensureDhparams: generating dhparams');
+    const dhparams = safe.child_process.execSync('openssl dhparam -dsaparam 2048');
+    if (!dhparams) throw new BoxError(BoxError.OPENSSL_ERROR, safe.error);
+    if (!safe.fs.writeFileSync(paths.DHPARAMS_FILE, dhparams)) throw new BoxError(BoxError.FS_ERROR, `Could not save dhparams.pem: ${safe.error.message}`);
+}
+
 async function unprovision() {
     // TODO: also cancel any existing configureWebadmin task
     await settings.setDashboardLocation('', '');
@@ -63,6 +72,7 @@ async function setupTask(domain, auditSource) {
 
     try {
         await cloudron.setupDnsAndCert(constants.DASHBOARD_LOCATION, domain, auditSource, (progress) => setProgress('setup', progress.message));
+        await ensureDhparams();
         await cloudron.setDashboardDomain(domain, auditSource);
         setProgress('setup', 'Done'),
         await eventlog.add(eventlog.ACTION_PROVISION, auditSource, {});
@@ -160,6 +170,7 @@ async function restoreTask(backupConfig, backupId, sysinfoConfig, options, audit
         const mailRestoreConfig = { backupConfig, backupId: mailBackups[0].id, backupFormat: mailBackups[0].format };
         await backuptask.downloadMail(mailRestoreConfig, (progress) => setProgress('restore', progress.message));
 
+        await ensureDhparams();
         await settings.setSysinfoConfig(sysinfoConfig);
         await reverseProxy.restoreFallbackCertificates();