PHP安全编程

ini_set(‘error_reporting‘, E_ALL | E_STRICT);
ini_set(‘display_errors‘, ‘Off‘);
ini_set(‘log_errors‘, ‘On‘);
ini_set(‘error_log‘, ‘/usr/local/apache/logs/error_log‘);

set_error_handler(‘my_error_handler‘);

function my_error_handler($number, $string, $file, $line, $context)
{
  $error = "= == == == ==\nPHP ERROR\n= == == == ==\n";
  $error .= "Number: [$number]\n";
  $error .= "String: [$string]\n";
  $error .= "File: [$file]\n";
  $error .= "Line: [$line]\n";
  $error .= "Context:\n" . print_r($context, TRUE) . "\n\n";
  error_log($error, 3, ‘/usr/local/apache/logs/error_log‘);
}

$salt = ‘SHIFLETT‘;
$identifier = md5($salt . md5($username . $salt));
$token = md5(uniqid(rand(), TRUE));
$timeout = time() + 60 * 60 * 24 * 7;
setcookie(‘auth‘, "$identifier:$token", $timeout);

$clean = array();
$mysql = array();
$now = time();
$salt = ‘SHIFLETT‘;
 
list($identifier, $token) = explode(‘:‘, $_COOKIE[‘auth‘]);
if (ctype_alnum($identifier) && ctype_alnum($token))
{
  $clean[‘identifier‘] = $identifier;
  $clean[‘token‘] = $token;
}
else
{
  /* ... */
}
 
$mysql[‘identifier‘] = mysql_real_escape_string($clean[‘identifier‘]);
$sql = "SELECT username, token, timeout
        FROM users
        WHERE identifier = ‘{$mysql[‘identifier‘]}‘";
if ($result = mysql_query($sql))
{
  if (mysql_num_rows($result))
  {
    $record = mysql_fetch_assoc($result);
    if ($clean[‘token‘] != $record[‘token‘])
    {
      /* Failed Login (wrong token) */
    }
    elseif ($now > $record[‘timeout‘])
    {
      /* Failed Login (timeout) */
    }
    elseif ($clean[‘identifier‘] != md5($salt . md5($record[‘username‘] . $salt)))
    {
      /* Failed Login (invalid identifier) */
    }
    else
    {
      /* Successful Login */
    }
  }
  else
  {
    /* Failed Login (invalid identifier) */
  }
}
else
{
  /* Error */
}

setcookie(‘auth‘, ‘DELETED!‘, time());