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