<?php

if ( getConfig('yubikey_enable', '1') != '1' )

    return true;

// hook into auth

$plugins->attachHook('login_process_userdata_json', 'return yubikey_auth_hook_json($userinfo, $req["level"], @$req["remember"]);');

// hook into special page init

$plugins->attachHook('session_started', 'yubikey_add_special_pages();');

// session key security

$plugins->attachHook('session_key_calc', 'yubikey_sk_calc($user_id, $key_pieces, $sk_mode);');

function yubikey_auth_hook_json(&$userdata, $level, $remember)

{

  global $db, $session, $paths, $template, $plugins; // Common objects

  global $lang;

  $do_validate_otp = false;

  $do_validate_user = false;

  $do_validate_pass = false;

  $user_flag = ( $level >= USER_LEVEL_CHPREF ) ? YK_SEC_ELEV_USERNAME : YK_SEC_NORMAL_USERNAME;

  $pass_flag = ( $level >= USER_LEVEL_CHPREF ) ? YK_SEC_ELEV_PASSWORD : YK_SEC_NORMAL_PASSWORD;

  $auth_log_prefix = ( $level >= USER_LEVEL_CHPREF ) ? 'admin_' : '';

  // Sort of a hack: if the password looks like an OTP and the OTP field is empty, use the password as the OTP

  if ( empty($userdata['yubikey_otp']) && preg_match('/^[cbdefghijklnrtuv]{44}$/', $userdata['password'] ) )

  {

    $userdata['yubikey_otp'] = $userdata['password'];

  }

  if ( !empty($userdata['username']) )

  {

    // get flags

    $q = $db->sql_query('SELECT user_id, user_yubikey_flags FROM ' . table_prefix . "users WHERE " . ENANO_SQLFUNC_LOWERCASE . "(username) = '" . $db->escape(strtolower($userdata['username'])) . "';");

    if ( !$q )

      $db->die_json();

    if ( $db->numrows() < 1 )

    {

      // Username not found - let the main login function handle it

      $db->free_result();

      return null;

    }

    list($user_id, $flags) = $db->fetchrow_num();

    $flags = intval($flags);

    // At the point the username is validated.

    $do_validate_user = false;

    $do_validate_pass = $flags & $pass_flag;

    if ( empty($userdata['yubikey_otp']) )

    {

      // no OTP was provided

      // make sure the user has allowed logging in with no OTP

      if ( !($flags & YK_SEC_ALLOW_NO_OTP) )

      {

        // We also might have no Yubikeys enrolled.

        $q = $db->sql_query('SELECT 1 FROM ' . table_prefix . "yubikey WHERE user_id = $user_id;");

        if ( !$q )

          $db->die_json();

        if ( $db->numrows() > 0 )

        {

          // Yep at least one key is enrolled.

          // I don't think these should be logged because they'll usually just be innocent mistakes.

          $db->free_result();

          return array(

              'mode' => 'error',

              'error' => 'yubiauth_err_must_have_otp'

            );

        }

        // Nope, no keys enrolled, user hasn't enabled Yubikey support

        $db->free_result();

      }

      // we're ok, use normal password auth

      return null;

    }

    else

    {

      // user did enter an OTP; make sure it's associated with the username

      $yubi_uid = $db->escape(substr($userdata['yubikey_otp'], 0, 12));

      $q = $db->sql_query('SELECT 1 FROM ' . table_prefix . 'yubikey WHERE yubi_uid = \'' . $yubi_uid . '\';');

      if ( !$q )

        $db->die_json();

      if ( $db->numrows() < 1 )

      {

        $db->free_result();

        return array(

            'mode' => 'error',

            'error' => 'yubiauth_err_key_not_authorized'

          );

      }

      $db->free_result();

      $do_validate_otp = true;

    }

  }

  else if ( !empty($userdata['yubikey_otp']) )

  {

    // we have an OTP, but no username to work with

    $yubi_uid = substr($userdata['yubikey_otp'], 0, 12);

    if ( !preg_match('/^[cbdefghijklnrtuv]{12}$/', $yubi_uid ) )

    {

      return array(

          'mode' => 'error',

          'error' => 'yubiauth_err_invalid_otp'

        );

    }

    $q = $db->sql_query('SELECT u.user_id, u.username, u.user_yubikey_flags FROM ' . table_prefix . "users AS u\n"

                      . "  LEFT JOIN " . table_prefix . "yubikey AS y\n"

                      . "    ON ( y.user_id = u.user_id )\n"

                      . "  WHERE y.yubi_uid = '$yubi_uid'\n"

                      . "  GROUP BY u.user_yubikey_flags;");

    if ( !$q )

      $db->_die();

    if ( $db->numrows() < 1 )

    {

      if ( !$do_validate_pass )

        $session->sql('INSERT INTO ' . table_prefix . "logs(log_type,action,time_id,date_string,author,edit_summary,page_text) VALUES\n"

                   . '  (\'security\', \'' . $auth_log_prefix . 'auth_bad\', '.time().', \''.enano_date('d M Y h:i a').'\', \'(Yubikey)\', '

                      . '\''.$db->escape($_SERVER['REMOTE_ADDR']).'\', ' . intval($level) . ')');

      return array(

          'mode' => 'error',

          'error' => 'yubiauth_err_key_not_authorized'

        );

    }

    list($user_id, $username, $flags) = $db->fetchrow_num();

    $do_validate_otp = true;

    $do_validate_user = $flags & $user_flag;

    $do_validate_pass = $flags & $pass_flag;

  }

  else

  {

    // Nothing - no username or OTP. This request can't be used; throw it out.

    return array(

        'mode' => 'error',

        'error' => 'yubiauth_err_nothing_provided'

      );

  }

  if ( $do_validate_otp )

  {

    // We need to validate the OTP.

    $otp_check = yubikey_validate_otp($userdata['yubikey_otp']);

    if ( !$otp_check['success'] )

    {

      if ( !$do_validate_pass )

        $session->sql('INSERT INTO ' . table_prefix . "logs(log_type,action,time_id,date_string,author,edit_summary,page_text) VALUES\n"

                   . '  (\'security\', \'' . $auth_log_prefix . 'auth_bad\', '.time().', \''.enano_date('d M Y h:i a').'\', \'(Yubikey)\', '

                      . '\''.$db->escape($_SERVER['REMOTE_ADDR']).'\', ' . intval($level) . ')');

      if ( $otp_check['error'] === 'http_failed' )

      {

        return array(

            'mode' => 'error',

            'error' => 'yubiauth_err_' . $otp_check['error'],

            'http_error' => $otp_check['http_error']

          );

      }

      return array(

          'mode' => 'error',

          'error' => 'yubiauth_err_' . $otp_check['error']

        );

    }

  }

  if ( $do_validate_user )

  {

    if ( empty($username) )

    {

      return array(

          'mode' => 'error',

          'error' => 'yubiauth_err_must_have_username'

        );

    }

    if ( strtolower($username) !== strtolower($userdata['username']) )

    {

      // Username incorrect

      if ( !$do_validate_pass )

        $session->sql('INSERT INTO ' . table_prefix . "logs(log_type,action,time_id,date_string,author,edit_summary,page_text) VALUES\n"

                   . '  (\'security\', \'' . $auth_log_prefix . 'auth_bad\', '.time().', \''.enano_date('d M Y h:i a').'\', \'(Yubikey)\', '

                      . '\''.$db->escape($_SERVER['REMOTE_ADDR']).'\', ' . intval($level) . ')');

      return array(

          'mode' => 'error',

          'error' => 'invalid_credentials'

        );

    }

  }

  // Do we need to have the password validated?

  if ( $do_validate_pass )

  {

    if ( empty($userdata['password']) )

    {

      return array(

          'mode' => 'error',

          'error' => 'yubiauth_err_must_have_password'

        );

    }

    // Yes; return and let the login API continue

    return null;

  }

  else

  {

    // No password required; validated, issue session key

    $session->sql('INSERT INTO ' . table_prefix . "logs(log_type,action,time_id,date_string,author,edit_summary,page_text) VALUES\n"

                   . '  (\'security\', \'' . $auth_log_prefix . 'auth_good\', '.time().', \''.enano_date('d M Y h:i a').'\', \'' . $db->escape($userdata['username']) . '\', '

                      . '\''.$db->escape($_SERVER['REMOTE_ADDR']).'\', ' . intval($level) . ')');

    $q = $db->sql_query('SELECT password FROM ' . table_prefix . "users WHERE user_id = $user_id;");

    if ( !$q )

      $db->_die();

    list($password) = $db->fetchrow_num();

    $db->free_result();

    $session->register_session($user_id, $userdata['username'], $password, $level, $remember);

    return true;

  }

}

function yubikey_add_special_pages()

{

  global $db, $session, $paths, $template, $plugins; // Common objects

  global $lang;

  if ( getConfig('yubikey_enable', '1') != '1' )

    return true;

  $paths->add_page(array(

      'name' => $lang->get('yubiauth_specialpage_yubikey'),

      'urlname' => 'Yubikey',

      'namespace' => 'Special',

      'visible' => 0, 'protected' => 0, 'comments_on' => 0, 'special' => 0

    ));

}

function yubikey_sk_calc($user_id, &$key_pieces, &$sk_mode)

{

  global $db, $session, $paths, $template, $plugins; // Common objects

  // hash the user's yubikeys

  $q = $db->sql_query('SELECT yubi_uid FROM ' . table_prefix . "yubikey WHERE user_id = $user_id;");

  if ( !$q )

    $db->_die();

  while ( $row = $db->fetchrow() )

  {

    $key_pieces[] = $row['yubi_uid'];

  }

}

function page_Special_Yubikey()

{

  global $db, $session, $paths, $template, $plugins; // Common objects

  header('Content-type: text/javascript');

  /*

  if ( isset($_GET['validate_otp']) )

  {

    echo enano_json_encode(yubikey_validate_otp($_GET['validate_otp']));

    return true;

  }

  */

  if ( isset($_GET['get_flags']) || isset($_POST['get_flags']) )

  {

    $yubi_uid = substr($_REQUEST['get_flags'], 0, 12);

    if ( !preg_match('/^[cbdefghijklnrtuv]{12}$/', $yubi_uid) )

    {

      return print enano_json_encode(array(

          'mode' => 'error',

          'error' => 'invalid_otp'

        ));

    }

    $q = $db->sql_query('SELECT u.user_yubikey_flags FROM ' . table_prefix . "users AS u\n"

                      . "  LEFT JOIN " . table_prefix . "yubikey AS y\n"

                      . "    ON ( y.user_id = u.user_id )\n"

                      . "  WHERE y.yubi_uid = '$yubi_uid'\n"

                      . "  GROUP BY u.user_yubikey_flags;");

    if ( !$q )

      $db->_die();

    if ( $db->numrows() < 1 )

    {

      return print enano_json_encode(array(

          'mode' => 'error',

          'error' => 'key_not_authorized'

        ));

    }

    list($flags) = $db->fetchrow_num();

    echo enano_json_encode(array(

        // We strip YK_SEC_ALLOW_NO_OTP here for security reasons.

        'flags' => intval($flags & ~YK_SEC_ALLOW_NO_OTP)

      ));

    return true;

  }

}