<?php /** * Implements data: URI for base64 encoded images supported by GD. */ class HTMLPurifier_URIScheme_data extends HTMLPurifier_URIScheme { /** * @type bool */ public $browsable = true; /** * @type array */ public $allowed_types = array( // you better write validation code for other types if you // decide to allow them 'image/jpeg' => true, 'image/gif' => true, 'image/png' => true, ); // this is actually irrelevant since we only write out the path // component /** * @type bool */ public $may_omit_host = true; /** * @param HTMLPurifier_URI $uri * @param HTMLPurifier_Config $config * @param HTMLPurifier_Context $context * @return bool */ public function doValidate(&$uri, $config, $context) { $result = explode(',', $uri->path, 2); $is_base64 = false; $charset = null; $content_type = null; if (count($result) == 2) { list($metadata, $data) = $result; // do some legwork on the metadata $metas = explode(';', $metadata); while (!empty($metas)) { $cur = array_shift($metas); if ($cur == 'base64') { $is_base64 = true; break; } if (substr($cur, 0, 8) == 'charset=') { // doesn't match if there are arbitrary spaces, but // whatever dude if ($charset !== null) { continue; } // garbage $charset = substr($cur, 8); // not used } else { if ($content_type !== null) { continue; } // garbage $content_type = $cur; } } } else { $data = $result[0]; } if ($content_type !== null && empty($this->allowed_types[$content_type])) { return false; } if ($charset !== null) { // error; we don't allow plaintext stuff $charset = null; } $data = rawurldecode($data); if ($is_base64) { $raw_data = base64_decode($data); } else { $raw_data = $data; } if ( strlen($raw_data) < 12 ) { // error; exif_imagetype throws exception with small files, // and this likely indicates a corrupt URI/failed parse anyway return false; } // XXX probably want to refactor this into a general mechanism // for filtering arbitrary content types if (function_exists('sys_get_temp_dir')) { $file = tempnam(sys_get_temp_dir(), ""); } else { $file = tempnam("/tmp", ""); } file_put_contents($file, $raw_data); if (function_exists('exif_imagetype')) { $image_code = exif_imagetype($file); unlink($file); } elseif (function_exists('getimagesize')) { set_error_handler(array($this, 'muteErrorHandler')); $info = getimagesize($file); restore_error_handler(); unlink($file); if ($info == false) { return false; } $image_code = $info[2]; } else { trigger_error("could not find exif_imagetype or getimagesize functions", E_USER_ERROR); } $real_content_type = image_type_to_mime_type($image_code); if ($real_content_type != $content_type) { // we're nice guys; if the content type is something else we // support, change it over if (empty($this->allowed_types[$real_content_type])) { return false; } $content_type = $real_content_type; } // ok, it's kosher, rewrite what we need $uri->userinfo = null; $uri->host = null; $uri->port = null; $uri->fragment = null; $uri->query = null; $uri->path = "$content_type;base64," . base64_encode($raw_data); return true; } /** * @param int $errno * @param string $errstr */ public function muteErrorHandler($errno, $errstr) { } }