phpmyadmin/src/Sanitize.php

<?php

/**
 * This class includes various sanitization methods that can be called statically
 */

declare(strict_types=1);

namespace PhpMyAdmin;

use PhpMyAdmin\Html\MySQLDocumentation;
use Twig\Attribute\AsTwigFilter;
use Twig\Attribute\AsTwigFunction;

use function __;
use function count;
use function json_encode;
use function preg_match;
use function preg_replace;
use function preg_replace_callback;
use function str_starts_with;
use function strtolower;
use function strtr;

use const JSON_HEX_TAG;

/**
 * This class includes various sanitization methods that can be called statically
 */
class Sanitize
{
    /**
     * Interpret bb code
     *
     * @var array<string, string>
     */
    private static array $replacePairs = [];

    /**
     * Checks whether given link is valid
     *
     * @param string $url   URL to check
     * @param bool   $http  Whether to allow http links
     * @param bool   $other Whether to allow ftp and mailto links
     */
    public static function checkLink(string $url, bool $http = false, bool $other = false): bool
    {
        $url = strtolower($url);
        $validStarts = ['https://', 'index.php?route=/url&url=https%3a%2f%2f', './docs/html/', './index.php?'];
        $isSetup = self::isSetup();
        // Adjust path to setup script location
        if ($isSetup) {
            foreach ($validStarts as $key => $value) {
                if (! str_starts_with($value, './')) {
                    continue;
                }

                $validStarts[$key] = '.' . $value;
            }
        }

        if ($other) {
            $validStarts[] = 'mailto:';
            $validStarts[] = 'ftp://';
        }

        if ($http) {
            $validStarts[] = 'http://';
        }

        if ($isSetup) {
            $validStarts[] = '?page=form&';
            $validStarts[] = '?page=servers&';
        }

        foreach ($validStarts as $val) {
            if (str_starts_with($url, $val)) {
                return true;
            }
        }

        return false;
    }

    /**
     * Check if we are currently on a setup folder page
     */
    private static function isSetup(): bool
    {
        return Config::getInstance()->isSetup();
    }

    /**
     * Callback function for replacing [a@link@target] links in bb code.
     *
     * @param string[] $found Array of preg matches
     *
     * @return string Replaced string
     */
    private static function replaceBBLink(array $found): string
    {
        /* Check for valid link */
        if (! self::checkLink($found[1])) {
            return $found[0];
        }

        /* a-z and _ allowed in target */
        if (! empty($found[3]) && preg_match('/[^a-z_]+/i', $found[3]) === 1) {
            return $found[0];
        }

        /* Construct target */
        $target = '';
        if (! empty($found[3])) {
            $target = ' target="' . $found[3] . '"';
            if ($found[3] === '_blank') {
                $target .= ' rel="noopener noreferrer"';
            }
        }

        /* Construct url */
        if (str_starts_with($found[1], 'http')) {
            $url = Core::linkURL($found[1]);
        } else {
            $url = $found[1];
        }

        return '<a href="' . $url . '"' . $target . '>';
    }

    /**
     * Callback function for replacing [doc@anchor] links in bb code.
     *
     * @param string[] $found Array of preg matches
     */
    private static function replaceDocLink(array $found): string
    {
        if (count($found) >= 4) {
            /* doc@page@anchor pattern */
            $page = $found[1];
            $anchor = $found[3];
        } else {
            /* doc@anchor pattern */
            $anchor = $found[1];
            if (str_starts_with($anchor, 'faq')) {
                $page = 'faq';
            } elseif (str_starts_with($anchor, 'cfg')) {
                $page = 'config';
            } else {
                /* Guess */
                $page = 'setup';
            }
        }

        $link = MySQLDocumentation::getDocumentationLink($page, $anchor, self::isSetup() ? '../' : './');

        return '<a href="' . $link . '" target="documentation">';
    }

    /**
     * Sanitizes $message, taking into account our special codes for formatting.
     *
     * @param string $message the message
     * @param bool   $safe    whether string is safe (can keep < and > chars)
     */
    #[AsTwigFilter('sanitize', isSafe: ['html'])]
    public static function convertBBCode(string $message, bool $safe = false): string
    {
        if (! $safe) {
            $message = strtr($message, ['<' => '&lt;', '>' => '&gt;', '"' => '&quot;', "'" => '&#039;']);
        }

        if (self::$replacePairs === []) {
            self::$replacePairs = [
                '[em]' => '<em>',
                '[/em]' => '</em>',
                '[strong]' => '<strong>',
                '[/strong]' => '</strong>',
                '[code]' => '<code>',
                '[/code]' => '</code>',
                '[kbd]' => '<kbd>',
                '[/kbd]' => '</kbd>',
                '[br]' => '<br>',
                '[/a]' => '</a>',
                '[/doc]' => '</a>',
                '[sup]' => '<sup>',
                '[/sup]' => '</sup>',
                // used in libraries/Util.php
                '[dochelpicon]' => Html\Generator::getImage('b_help', __('Documentation')),
            ];
        }

        $message = strtr($message, self::$replacePairs);

        /* Match links in bb code ([a@url@target], where @target is options) */
        $pattern = '/\[a@([^]"@]*)(@([^]"]*))?\]/';

        /* Find and replace all links */
        $message = (string) preg_replace_callback(
            $pattern,
            self::replaceBBLink(...),
            $message,
        );

        /* Replace documentation links */
        return (string) preg_replace_callback(
            '/\[doc@([a-zA-Z0-9_-]+)(@([a-zA-Z0-9_-]*))?\]/',
            /** @param string[] $match */
            self::replaceDocLink(...),
            $message,
        );
    }

    /**
     * Sanitize a filename by removing anything besides legit characters
     *
     * Intended usecase:
     *    When using a filename in a Content-Disposition header
     *    the value should not contain ; or "
     *
     *    When exporting, avoiding generation of an unexpected double-extension file
     *
     * @param string $filename    The filename
     * @param bool   $replaceDots Whether to also replace dots
     *
     * @return string  the sanitized filename
     */
    public static function sanitizeFilename(string $filename, bool $replaceDots = false): string
    {
        // Keep only numbers (N), letters (L), dash, underbar, and maybe dot
        $pattern = '/[^\p{N}\p{L}' . ($replaceDots ? '' : '.') . '_-]/u';

        return preg_replace($pattern, '_', $filename);
    }

    /**
     * Formats an javascript assignment with proper escaping of a value
     * and support for assigning array of strings.
     *
     * @param string $key   Name of value to set
     * @param mixed  $value Value to set, can be either string or array of strings
     *
     * @return string Javascript code.
     */
    #[AsTwigFunction('get_js_value', isSafe: ['html'])]
    public static function getJsValue(string $key, mixed $value): string
    {
        return $key . ' = ' . json_encode($value, JSON_HEX_TAG) . ";\n";
    }
}