Generate QR codes for TOTP tokens

Summary: Ref T4398. I found a reasonable-ish LGPLv3 library for doing this, which isn't too huge or unwieldy.

Test Plan:
  - Scanned QR code with Authy.
  - Scanned QR code with Google Authenticator.

{F149317}

Reviewers: btrahan

Reviewed By: btrahan

Subscribers: epriestley

Maniphest Tasks: T4398

Differential Revision: https://secure.phabricator.com/D8923

externals/phpqrcode/LICENSE

@@ -0,0 +1,165 @@
+                  GNU LESSER GENERAL PUBLIC LICENSE
+                       Version 3, 29 June 2007
+
+ Copyright (C) 2007 Free Software Foundation, Inc. <http://fsf.org/>
+ Everyone is permitted to copy and distribute verbatim copies
+ of this license document, but changing it is not allowed.
+
+
+  This version of the GNU Lesser General Public License incorporates
+the terms and conditions of version 3 of the GNU General Public
+License, supplemented by the additional permissions listed below.
+
+  0. Additional Definitions.
+
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+General Public License, and the "GNU GPL" refers to version 3 of the GNU
+General Public License.
+
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+other than an Application or a Combined Work as defined below.
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externals/phpqrcode/README

@@ -0,0 +1,45 @@
+This is PHP implementation of QR Code 2-D barcode generator. It is pure-php
+LGPL-licensed implementation based on C libqrencode by Kentaro Fukuchi.
+
+== LICENSING ==
+
+Copyright (C) 2010 by Dominik Dzienia 
+
+This library is free software; you can redistribute it and/or modify it under
+the terms of the GNU Lesser General Public License as published by the Free
+Software Foundation; either version 3 of the License, or any later version.
+
+This library is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
+PARTICULAR PURPOSE. See the GNU Lesser General Public License (LICENSE file)
+for more details.
+
+You should have received a copy of the GNU Lesser General Public License along
+with this library; if not, write to the Free Software Foundation, Inc., 51
+Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+
+== INSTALATION AND USAGE ==
+
+ * INSTALL file
+ * http://sourceforge.net/apps/mediawiki/phpqrcode/index.php?title=Main_Page
+
+== CONTACT ==
+
+Fell free to contact me via e-mail (deltalab at poczta dot fm) or using
+folowing project pages:
+
+ * http://sourceforge.net/projects/phpqrcode/
+ * http://phpqrcode.sourceforge.net/
+  
+== ACKNOWLEDGMENTS ==
+
+Based on C libqrencode library (ver. 3.1.1) 
+Copyright (C) 2006-2010 by Kentaro Fukuchi
+http://megaui.net/fukuchi/works/qrencode/index.en.html
+
+QR Code is registered trademarks of DENSO WAVE INCORPORATED in JAPAN and other
+countries.
+
+Reed-Solomon code encoder is written by Phil Karn, KA9Q.
+Copyright (C) 2002, 2003, 2004, 2006 Phil Karn, KA9Q
+ 

externals/phpqrcode/VERSION

@@ -0,0 +1,2 @@
+1.1.4
+2010100721

src/applications/auth/factor/PhabricatorAuthFactorTOTP.php

@@ -22,7 +22,6 @@ final class PhabricatorAuthFactorTOTP extends PhabricatorAuthFactor {
     AphrontRequest $request,
     PhabricatorUser $user) {
 
-
     $key = $request->getStr('totpkey');
     if (!strlen($key)) {
       // TODO: When the user submits a key, we should require that it be
@@ -69,8 +68,21 @@ final class PhabricatorAuthFactorTOTP extends PhabricatorAuthFactor {
     $form->appendInstructions(
       pht(
         'Launch the application on your phone, and add a new entry for '.
-        'this Phabricator install. When prompted, enter the key shown '.
+        'this Phabricator install. When prompted, scan the QR code or '.
-        'below into the application.'));
+        'manually enter the key shown below into the application.'));
+
+    $prod_uri = new PhutilURI(PhabricatorEnv::getProductionURI('/'));
+    $issuer = $prod_uri->getDomain();
+
+    $uri = urisprintf(
+      'otpauth://totp/%s:%s?secret=%s&issuer=%s',
+      $issuer,
+      $user->getUsername(),
+      $key,
+      $issuer);
+
+    $qrcode = $this->renderQRCode($uri);
+    $form->appendChild($qrcode);
 
     $form->appendChild(
       id(new AphrontFormStaticControl())
@@ -219,4 +231,47 @@ final class PhabricatorAuthFactorTOTP extends PhabricatorAuthFactor {
     return $code;
   }
 
+
+  /**
+   * @phutil-external-symbol class QRcode
+   */
+  private function renderQRCode($uri) {
+    $root = dirname(phutil_get_library_root('phabricator'));
+    require_once $root.'/externals/phpqrcode/phpqrcode.php';
+
+    $lines = QRcode::text($uri);
+
+    $total_width = 240;
+    $cell_size = floor($total_width / count($lines));
+
+    $rows = array();
+    foreach ($lines as $line) {
+      $cells = array();
+      for ($ii = 0; $ii < strlen($line); $ii++) {
+        if ($line[$ii] == '1') {
+          $color = '#000';
+        } else {
+          $color = '#fff';
+        }
+
+        $cells[] = phutil_tag(
+          'td',
+          array(
+            'width' => $cell_size,
+            'height' => $cell_size,
+            'style' => 'background: '.$color,
+          ),
+          '');
+      }
+      $rows[] = phutil_tag('tr', array(), $cells);
+    }
+
+    return phutil_tag(
+      'table',
+      array(
+        'style' => 'margin: 24px auto;',
+      ),
+      $rows);
+  }
+
 }