parsedown = new \Parsedown(); $this->escape = $conf->get('security.markdown_escape', true); $this->allowedProtocols = $conf->get('security.allowed_protocols', []); } /** * @inheritdoc */ public function formatDescription($bookmark) { if (in_array(self::NO_MD_TAG, $bookmark->getTags())) { return parent::formatDescription($bookmark); } $processedDescription = $bookmark->getDescription(); $processedDescription = $this->filterProtocols($processedDescription); $processedDescription = $this->formatHashTags($processedDescription); $processedDescription = $this->parsedown ->setMarkupEscaped($this->escape) ->setBreaksEnabled(true) ->text($processedDescription); $processedDescription = $this->sanitizeHtml($processedDescription); if (!empty($processedDescription)) { $processedDescription = '
'. $processedDescription . '
'; } return $processedDescription; } /** * Remove the NO markdown tag if it is present * * @inheritdoc */ protected function formatTagList($bookmark) { $out = parent::formatTagList($bookmark); if (($pos = array_search(self::NO_MD_TAG, $out)) !== false) { unset($out[$pos]); return array_values($out); } return $out; } /** * Replace not whitelisted protocols with http:// in given description. * Also adds `index_url` to relative links if it's specified * * @param string $description input description text. * * @return string $description without malicious link. */ protected function filterProtocols($description) { $allowedProtocols = $this->allowedProtocols; $indexUrl = ! empty($this->contextData['index_url']) ? $this->contextData['index_url'] : ''; return preg_replace_callback( '#]\((.*?)\)#is', function ($match) use ($allowedProtocols, $indexUrl) { $link = startsWith($match[1], '?') || startsWith($match[1], '/') ? $indexUrl : ''; $link .= whitelist_protocols($match[1], $allowedProtocols); return ']('. $link.')'; }, $description ); } /** * Replace hashtag in Markdown links format * E.g. `#hashtag` becomes `[#hashtag](?addtag=hashtag)` * It includes the index URL if specified. * * @param string $description * * @return string */ protected function formatHashTags($description) { $indexUrl = ! empty($this->contextData['index_url']) ? $this->contextData['index_url'] : ''; /* * To support unicode: http://stackoverflow.com/a/35498078/1484919 * \p{Pc} - to match underscore * \p{N} - numeric character in any script * \p{L} - letter from any language * \p{Mn} - any non marking space (accents, umlauts, etc) */ $regex = '/(^|\s)#([\p{Pc}\p{N}\p{L}\p{Mn}]+)/mui'; $replacement = '$1[#$2]('. $indexUrl .'?addtag=$2)'; $descriptionLines = explode(PHP_EOL, $description); $descriptionOut = ''; $codeBlockOn = false; $lineCount = 0; foreach ($descriptionLines as $descriptionLine) { // Detect line of code: starting with 4 spaces, // except lists which can start with +/*/- or `2.` after spaces. $codeLineOn = preg_match('/^ +(?=[^\+\*\-])(?=(?!\d\.).)/', $descriptionLine) > 0; // Detect and toggle block of code if (!$codeBlockOn) { $codeBlockOn = preg_match('/^```/', $descriptionLine) > 0; } elseif (preg_match('/^```/', $descriptionLine) > 0) { $codeBlockOn = false; } if (!$codeBlockOn && !$codeLineOn) { $descriptionLine = preg_replace($regex, $replacement, $descriptionLine); } $descriptionOut .= $descriptionLine; if ($lineCount++ < count($descriptionLines) - 1) { $descriptionOut .= PHP_EOL; } } return $descriptionOut; } /** * Remove dangerous HTML tags (tags, iframe, etc.). * Doesn't affect content (already escaped by Parsedown). * * @param string $description input description text. * * @return string given string escaped. */ protected function sanitizeHtml($description) { $escapeTags = array( 'script', 'style', 'link', 'iframe', 'frameset', 'frame', ); foreach ($escapeTags as $tag) { $description = preg_replace_callback( '#<\s*'. $tag .'[^>]*>(.*]*>)?#is', function ($match) { return escape($match[0]); }, $description ); } $description = preg_replace( '#(<[^>]+\s)on[a-z]*="?[^ "]*"?#is', '$1', $description ); return $description; } }