clamav.module

<?php
// $Id$
/**
 * @file
 * Integrate ClamAV to allow uploaded files to be scanned for viruses.
 */

// Scan using a ClamAV Daemon
define('CLAMAV_USE_DAEMON', 0);
// Scan using a ClamAV executable
define('CLAMAV_USE_EXECUTABLE', 1);
// Default: use Daemon-mode
define('CLAMAV_DEFAULT_MODE', CLAMAV_USE_DAEMON);

// Behaviour if the ClamAV scanner is unavailable or does not respond.
// Prevent unchecked files from being uploaded
define('CLAMAV_BLOCK_UNCHECKED', 0);
// Allow unchecked files to be uploaded
define('CLAMAV_ALLOW_UNCHECKED', 1);
// Default behaviour for unchecked files - Block unchecked files.
define('CLAMAV_DEFAULT_UNCHECKED', CLAMAV_BLOCK_UNCHECKED);

// Default host (in Daemon-mode)
define('CLAMAV_DEFAULT_HOST', 'localhost');
// Default port (in Daemon-mode)
define('CLAMAV_DEFAULT_PORT', 3310);
// Default path (in Executable-mode)
define('CLAMAV_DEFAULT_PATH', '/usr/bin/clamscan');

// The file was not checked (e.g. because the AV daemon wasn't running).
define('CLAMAV_SCANRESULT_UNCHECKED', -1);
// The file was checked and found to be clean.
define('CLAMAV_SCANRESULT_CLEAN', 0);
// The file was checked and found to be infected.
define('CLAMAV_SCANRESULT_INFECTED', 1);

/**
 * Implementation of hook_help().
 */
function clamav_help($path, $arg) {
  $output = '';
  switch ($path) {
    case "admin/help#clamav":
      $output .= '<p>' . t('Clam AntiVirus is an open source anti-virus toolkit for UNIX.') . '</p>';
      $output .= '<p>' . t('The ClamAV module allows files which are uploaded to Drupal to be scanned by Clam AntiVirus.') . '<br />';
      $output .=         t('The module does not install ClamAV - visit <a href="http://www.clamav.net/">the ClamAV website</a> for help installing ClamAV.') . '</p>';
      break;

    case 'admin/settings/clamav':
      break;
  }
  return $output;
}

/**
 * Implementation of hook_menu().
 */
function clamav_menu() {
  return array(
    'admin/settings/clamav' => array(
      'title' => 'Anti-virus (ClamAV)',
      'page callback' => 'drupal_get_form',
      'page arguments' => array('clamav_admin_settings'),
      'access arguments' => array('administer site configuration'),
      'file' => 'clamav.admin.inc',
    ),
  );
}

/**
 * Implementation of hook_elements().
 */
function clamav_elements() {
  $elements = array();
  // support the core 'file' FAPI element.
  if (variable_get('clamav_enable_element_file', TRUE)) {
    $elements['file']['#element_validate'] = array('clamav_elements_file_validate');
  }
  return $elements;
}

/**
 * Form element validator for the file FAPI type.
 *
 * @param Array $element
 */
function clamav_elements_file_validate($element) {
  $key = $element['#parents'][0];
  if (array_key_exists($key, $_FILES['files']['tmp_name']) && !empty($_FILES['files']['tmp_name'][$key])) {
    $filepath = $_FILES['files']['tmp_name'][$key];         // filepath to the uploaded file
    $form_error_key = implode('][', $element['#parents']);  // form-element to use with form_set_error

    require_once(dirname(__FILE__) . '/clamav.inc');
    clamav_scan($filepath, $form_error_key);
  }
}

/**
 * Implementation of hook_form_alter().
 * Validation of CCK filefield and imagefield is applied here.
 */
function clamav_form_alter(&$form, $form_state, $form_id) {
  if (isset($form['type']) && isset($form['#node']) && $form['type']['#value'] .'_node_form' == $form_id) {
    $type = content_types($form['#node']->type);
    if (!empty($type['fields'])) {
      foreach ($type['fields'] as $field_name => $field) {
        $function = 'clamav_' . $field['widget']['type'] . '_alter';
        if (function_exists($function)) {
          $function($form[$field_name]);
        }
      }
    }
  }
}

/**
 * Implementation of our custom hook_FIELDNAME_alter for filefield widget.
 */
function clamav_filefield_widget_alter(&$field) {
  if (module_exists('filefield') && variable_get('clamav_enable_element_filefield_widget', TRUE)) {
    $field[0]['#upload_validators']['clamav_elements_filefield_validate'] = array();
  }
}

/**
 * Implementation of our custom hook_FIELDNAME_alter for filefield widget.
 */
function clamav_imagefield_widget_alter(&$field) {
  if (module_exists('imagefield') && variable_get('clamav_enable_element_imagefield_widget', TRUE)) {
    $field[0]['#upload_validators']['clamav_elements_filefield_validate'] = array();
  }
}

/**
 *  Validator for filefield widget and imagefield widget.
 *  This is an implementation of a file upload_validator.
 */
function clamav_elements_filefield_validate($file) {
  $filepath = $file->filepath;
  $form_error_key = $file->source;

  require_once(dirname(__FILE__) . '/clamav.inc');
  $result = clamav_scan_file($filepath);

  $errors = array();
  if ($result == CLAMAV_SCANRESULT_INFECTED) {
    $errors[] =  t('A virus has been detected in the file.  The file will not be accepted.');
  }
  elseif ($result == CLAMAV_SCANRESULT_UNCHECKED && variable_get('clamav_unchecked_files', CLAMAV_DEFAULT_UNCHECKED) == CLAMAV_BLOCK_UNCHECKED) {
    $errors[] = t('The anti-virus scanner was not able to check the file.  The file cannot be uploaded.');
  }
  return $errors;
}