PHPIndex

<?php

class HTMLPurifier_URIFilter_DisableExternal extends HTMLPurifier_URIFilter
{
    /**
     * @type string
     */
    public $name = 'DisableExternal';

    /**
     * @type array
     */
    protected $ourHostParts = false;

    /**
     * @param HTMLPurifier_Config $config
     * @return void
     */
    public function prepare($config)
    {
        $our_host = $config->getDefinition('URI')->host;
        if ($our_host !== null) {
            $this->ourHostParts = array_reverse(explode('.', $our_host));
        }
    }

    /**
     * @param HTMLPurifier_URI $uri Reference
     * @param HTMLPurifier_Config $config
     * @param HTMLPurifier_Context $context
     * @return bool
     */
    public function filter(&$uri, $config, $context)
    {
        if (is_null($uri->host)) {
            return true;
        }
        if ($this->ourHostParts === false) {
            return false;
        }
        $host_parts = array_reverse(explode('.', $uri->host));
        foreach ($this->ourHostParts as $i => $x) {
            if (!isset($host_parts[$i])) {
                return false;
            }
            if ($host_parts[$i] != $this->ourHostParts[$i]) {
                return false;
            }
        }
        return true;
    }
}

// vim: et sw=4 sts=4

<?php

class HTMLPurifier_URIFilter_DisableExternalResources extends HTMLPurifier_URIFilter_DisableExternal
{
    /**
     * @type string
     */
    public $name = 'DisableExternalResources';

    /**
     * @param HTMLPurifier_URI $uri
     * @param HTMLPurifier_Config $config
     * @param HTMLPurifier_Context $context
     * @return bool
     */
    public function filter(&$uri, $config, $context)
    {
        if (!$context->get('EmbeddedURI', true)) {
            return true;
        }
        return parent::filter($uri, $config, $context);
    }
}

// vim: et sw=4 sts=4

<?php

class HTMLPurifier_URIFilter_DisableResources extends HTMLPurifier_URIFilter
{
    /**
     * @type string
     */
    public $name = 'DisableResources';

    /**
     * @param HTMLPurifier_URI $uri
     * @param HTMLPurifier_Config $config
     * @param HTMLPurifier_Context $context
     * @return bool
     */
    public function filter(&$uri, $config, $context)
    {
        return !$context->get('EmbeddedURI', true);
    }
}

// vim: et sw=4 sts=4

<?php

// It's not clear to me whether or not Punycode means that hostnames
// do not have canonical forms anymore. As far as I can tell, it's
// not a problem (punycoding should be identity when no Unicode
// points are involved), but I'm not 100% sure
class HTMLPurifier_URIFilter_HostBlacklist extends HTMLPurifier_URIFilter
{
    /**
     * @type string
     */
    public $name = 'HostBlacklist';

    /**
     * @type array
     */
    protected $blacklist = array();

    /**
     * @param HTMLPurifier_Config $config
     * @return bool
     */
    public function prepare($config)
    {
        $this->blacklist = $config->get('URI.HostBlacklist');
        return true;
    }

    /**
     * @param HTMLPurifier_URI $uri
     * @param HTMLPurifier_Config $config
     * @param HTMLPurifier_Context $context
     * @return bool
     */
    public function filter(&$uri, $config, $context)
    {
        foreach ($this->blacklist as $blacklisted_host_fragment) {
            if ($uri->host !== null && strpos($uri->host, $blacklisted_host_fragment) !== false) {
                return false;
            }
        }
        return true;
    }
}

// vim: et sw=4 sts=4

<?php

// does not support network paths

class HTMLPurifier_URIFilter_MakeAbsolute extends HTMLPurifier_URIFilter
{
    /**
     * @type string
     */
    public $name = 'MakeAbsolute';

    /**
     * @type
     */
    protected $base;

    /**
     * @type array
     */
    protected $basePathStack = array();

    /**
     * @param HTMLPurifier_Config $config
     * @return bool
     */
    public function prepare($config)
    {
        $def = $config->getDefinition('URI');
        $this->base = $def->base;
        if (is_null($this->base)) {
            trigger_error(
                'URI.MakeAbsolute is being ignored due to lack of ' .
                'value for URI.Base configuration',
                E_USER_WARNING
            );
            return false;
        }
        $this->base->fragment = null; // fragment is invalid for base URI
        $stack = explode('/', $this->base->path);
        array_pop($stack); // discard last segment
        $stack = $this->_collapseStack($stack); // do pre-parsing
        $this->basePathStack = $stack;
        return true;
    }

    /**
     * @param HTMLPurifier_URI $uri
     * @param HTMLPurifier_Config $config
     * @param HTMLPurifier_Context $context
     * @return bool
     */
    public function filter(&$uri, $config, $context)
    {
        if (is_null($this->base)) {
            return true;
        } // abort early
        if ($uri->path === '' && is_null($uri->scheme) &&
            is_null($uri->host) && is_null($uri->query) && is_null($uri->fragment)) {
            // reference to current document
            $uri = clone $this->base;
            return true;
        }
        if (!is_null($uri->scheme)) {
            // absolute URI already: don't change
            if (!is_null($uri->host)) {
                return true;
            }
            $scheme_obj = $uri->getSchemeObj($config, $context);
            if (!$scheme_obj) {
                // scheme not recognized
                return false;
            }
            if (!$scheme_obj->hierarchical) {
                // non-hierarchal URI with explicit scheme, don't change
                return true;
            }
            // special case: had a scheme but always is hierarchical and had no authority
        }
        if (!is_null($uri->host)) {
            // network path, don't bother
            return true;
        }
        if ($uri->path === '') {
            $uri->path = $this->base->path;
        } elseif ($uri->path[0] !== '/') {
            // relative path, needs more complicated processing
            $stack = explode('/', $uri->path);
            $new_stack = array_merge($this->basePathStack, $stack);
            if ($new_stack[0] !== '' && !is_null($this->base->host)) {
                array_unshift($new_stack, '');
            }
            $new_stack = $this->_collapseStack($new_stack);
            $uri->path = implode('/', $new_stack);
        } else {
            // absolute path, but still we should collapse
            $uri->path = implode('/', $this->_collapseStack(explode('/', $uri->path)));
        }
        // re-combine
        $uri->scheme = $this->base->scheme;
        if (is_null($uri->userinfo)) {
            $uri->userinfo = $this->base->userinfo;
        }
        if (is_null($uri->host)) {
            $uri->host = $this->base->host;
        }
        if (is_null($uri->port)) {
            $uri->port = $this->base->port;
        }
        return true;
    }

    /**
     * Resolve dots and double-dots in a path stack
     * @param array $stack
     * @return array
     */
    private function _collapseStack($stack)
    {
        $result = array();
        $is_folder = false;
        for ($i = 0; isset($stack[$i]); $i++) {
            $is_folder = false;
            // absorb an internally duplicated slash
            if ($stack[$i] == '' && $i && isset($stack[$i + 1])) {
                continue;
            }
            if ($stack[$i] == '..') {
                if (!empty($result)) {
                    $segment = array_pop($result);
                    if ($segment === '' && empty($result)) {
                        // error case: attempted to back out too far:
                        // restore the leading slash
                        $result[] = '';
                    } elseif ($segment === '..') {
                        $result[] = '..'; // cannot remove .. with ..
                    }
                } else {
                    // relative path, preserve the double-dots
                    $result[] = '..';
                }
                $is_folder = true;
                continue;
            }
            if ($stack[$i] == '.') {
                // silently absorb
                $is_folder = true;
                continue;
            }
            $result[] = $stack[$i];
        }
        if ($is_folder) {
            $result[] = '';
        }
        return $result;
    }
}

// vim: et sw=4 sts=4

<?php

class HTMLPurifier_URIFilter_Munge extends HTMLPurifier_URIFilter
{
    /**
     * @type string
     */
    public $name = 'Munge';

    /**
     * @type bool
     */
    public $post = true;

    /**
     * @type string
     */
    private $target;

    /**
     * @type HTMLPurifier_URIParser
     */
    private $parser;

    /**
     * @type bool
     */
    private $doEmbed;

    /**
     * @type string
     */
    private $secretKey;

    /**
     * @type array
     */
    protected $replace = array();

    /**
     * @param HTMLPurifier_Config $config
     * @return bool
     */
    public function prepare($config)
    {
        $this->target = $config->get('URI.' . $this->name);
        $this->parser = new HTMLPurifier_URIParser();
        $this->doEmbed = $config->get('URI.MungeResources');
        $this->secretKey = $config->get('URI.MungeSecretKey');
        if ($this->secretKey && !function_exists('hash_hmac')) {
            throw new Exception("Cannot use %URI.MungeSecretKey without hash_hmac support.");
        }
        return true;
    }

    /**
     * @param HTMLPurifier_URI $uri
     * @param HTMLPurifier_Config $config
     * @param HTMLPurifier_Context $context
     * @return bool
     */
    public function filter(&$uri, $config, $context)
    {
        if ($context->get('EmbeddedURI', true) && !$this->doEmbed) {
            return true;
        }

        $scheme_obj = $uri->getSchemeObj($config, $context);
        if (!$scheme_obj) {
            return true;
        } // ignore unknown schemes, maybe another postfilter did it
        if (!$scheme_obj->browsable) {
            return true;
        } // ignore non-browseable schemes, since we can't munge those in a reasonable way
        if ($uri->isBenign($config, $context)) {
            return true;
        } // don't redirect if a benign URL

        $this->makeReplace($uri, $config, $context);
        $this->replace = array_map('rawurlencode', $this->replace);

        $new_uri = strtr($this->target, $this->replace);
        $new_uri = $this->parser->parse($new_uri);
        // don't redirect if the target host is the same as the
        // starting host
        if ($uri->host === $new_uri->host) {
            return true;
        }
        $uri = $new_uri; // overwrite
        return true;
    }

    /**
     * @param HTMLPurifier_URI $uri
     * @param HTMLPurifier_Config $config
     * @param HTMLPurifier_Context $context
     */
    protected function makeReplace($uri, $config, $context)
    {
        $string = $uri->toString();
        // always available
        $this->replace['%s'] = $string;
        $this->replace['%r'] = $context->get('EmbeddedURI', true) ?: '';
        $token = $context->get('CurrentToken', true) ?: '';
        $this->replace['%n'] = $token ? $token->name : '';
        $this->replace['%m'] = $context->get('CurrentAttr', true) ?: '';
        $this->replace['%p'] = $context->get('CurrentCSSProperty', true) ?: '';
        // not always available
        if ($this->secretKey) {
            $this->replace['%t'] = hash_hmac("sha256", $string, $this->secretKey);
        }
    }
}

// vim: et sw=4 sts=4

<?php

/**
 * Implements safety checks for safe iframes.
 *
 * @warning This filter is *critical* for ensuring that %HTML.SafeIframe
 * works safely.
 */
class HTMLPurifier_URIFilter_SafeIframe extends HTMLPurifier_URIFilter
{
    /**
     * @type string
     */
    public $name = 'SafeIframe';

    /**
     * @type bool
     */
    public $always_load = true;

    /**
     * @type string
     */
    protected $regexp = null;

    // XXX: The not so good bit about how this is all set up now is we
    // can't check HTML.SafeIframe in the 'prepare' step: we have to
    // defer till the actual filtering.
    /**
     * @param HTMLPurifier_Config $config
     * @return bool
     */
    public function prepare($config)
    {
        $this->regexp = $config->get('URI.SafeIframeRegexp');
        return true;
    }

    /**
     * @param HTMLPurifier_URI $uri
     * @param HTMLPurifier_Config $config
     * @param HTMLPurifier_Context $context
     * @return bool
     */
    public function filter(&$uri, $config, $context)
    {
        // check if filter not applicable
        if (!$config->get('HTML.SafeIframe')) {
            return true;
        }
        // check if the filter should actually trigger
        if (!$context->get('EmbeddedURI', true)) {
            return true;
        }
        $token = $context->get('CurrentToken', true);
        if (!($token && $token->name == 'iframe')) {
            return true;
        }
        // check if we actually have some whitelists enabled
        if ($this->regexp === null) {
            return false;
        }
        // actually check the whitelists
        return preg_match($this->regexp, $uri->toString());
    }
}

// vim: et sw=4 sts=4