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<?php |
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/** |
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* HTML Purifier's internal representation of a URI. |
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* @note |
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* Internal data-structures are completely escaped. If the data needs |
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* to be used in a non-URI context (which is very unlikely), be sure |
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* to decode it first. The URI may not necessarily be well-formed until |
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* validate() is called. |
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*/ |
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class HTMLPurifier_URI |
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{ |
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/** |
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* @type string |
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*/ |
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public $scheme; |
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/** |
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* @type string |
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*/ |
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public $userinfo; |
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/** |
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* @type string |
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*/ |
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public $host; |
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/** |
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* @type int |
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*/ |
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public $port; |
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/** |
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* @type string |
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*/ |
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public $path; |
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/** |
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* @type string |
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*/ |
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public $query; |
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/** |
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* @type string |
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*/ |
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public $fragment; |
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/** |
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* @param string $scheme |
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* @param string $userinfo |
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* @param string $host |
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* @param int $port |
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* @param string $path |
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* @param string $query |
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* @param string $fragment |
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* @note Automatically normalizes scheme and port |
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*/ |
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public function __construct($scheme, $userinfo, $host, $port, $path, $query, $fragment) |
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{ |
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$this->scheme = is_null($scheme) || ctype_lower($scheme) ? $scheme : strtolower($scheme); |
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$this->userinfo = $userinfo; |
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$this->host = $host; |
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$this->port = is_null($port) ? $port : (int)$port; |
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$this->path = $path; |
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$this->query = $query; |
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$this->fragment = $fragment; |
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} |
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/** |
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* Retrieves a scheme object corresponding to the URI's scheme/default |
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* @param HTMLPurifier_Config $config |
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* @param HTMLPurifier_Context $context |
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* @return HTMLPurifier_URIScheme Scheme object appropriate for validating this URI |
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*/ |
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public function getSchemeObj($config, $context) |
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{ |
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$registry = HTMLPurifier_URISchemeRegistry::instance(); |
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if ($this->scheme !== null) { |
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$scheme_obj = $registry->getScheme($this->scheme, $config, $context); |
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if (!$scheme_obj) { |
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return false; |
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} // invalid scheme, clean it out |
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} else { |
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// no scheme: retrieve the default one |
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$def = $config->getDefinition('URI'); |
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$scheme_obj = $def->getDefaultScheme($config, $context); |
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if (!$scheme_obj) { |
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if ($def->defaultScheme !== null) { |
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// something funky happened to the default scheme object |
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trigger_error( |
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'Default scheme object "' . $def->defaultScheme . '" was not readable', |
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E_USER_WARNING |
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); |
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} // suppress error if it's null |
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return false; |
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} |
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} |
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return $scheme_obj; |
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} |
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/** |
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* Generic validation method applicable for all schemes. May modify |
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* this URI in order to get it into a compliant form. |
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* @param HTMLPurifier_Config $config |
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* @param HTMLPurifier_Context $context |
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* @return bool True if validation/filtering succeeds, false if failure |
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*/ |
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public function validate($config, $context) |
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{ |
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// ABNF definitions from RFC 3986 |
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$chars_sub_delims = '!$&\'()*+,;='; |
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$chars_gen_delims = ':/?#[]@'; |
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$chars_pchar = $chars_sub_delims . ':@'; |
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// validate host |
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if (!is_null($this->host)) { |
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$host_def = new HTMLPurifier_AttrDef_URI_Host(); |
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$this->host = $host_def->validate($this->host, $config, $context); |
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if ($this->host === false) { |
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$this->host = null; |
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} |
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} |
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// validate scheme |
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// NOTE: It's not appropriate to check whether or not this |
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// scheme is in our registry, since a URIFilter may convert a |
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// URI that we don't allow into one we do. So instead, we just |
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// check if the scheme can be dropped because there is no host |
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// and it is our default scheme. |
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if (!is_null($this->scheme) && is_null($this->host) || $this->host === '') { |
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// support for relative paths is pretty abysmal when the |
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// scheme is present, so axe it when possible |
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$def = $config->getDefinition('URI'); |
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if ($def->defaultScheme === $this->scheme) { |
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$this->scheme = null; |
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} |
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} |
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// validate username |
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if (!is_null($this->userinfo)) { |
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$encoder = new HTMLPurifier_PercentEncoder($chars_sub_delims . ':'); |
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$this->userinfo = $encoder->encode($this->userinfo); |
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} |
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// validate port |
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if (!is_null($this->port)) { |
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if ($this->port < 1 || $this->port > 65535) { |
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$this->port = null; |
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} |
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} |
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// validate path |
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$segments_encoder = new HTMLPurifier_PercentEncoder($chars_pchar . '/'); |
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if (!is_null($this->host)) { // this catches $this->host === '' |
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// path-abempty (hier and relative) |
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// http://www.example.com/my/path |
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// //www.example.com/my/path (looks odd, but works, and |
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// recognized by most browsers) |
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// (this set is valid or invalid on a scheme by scheme |
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// basis, so we'll deal with it later) |
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// file:///my/path |
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// ///my/path |
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$this->path = $segments_encoder->encode($this->path); |
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} elseif ($this->path !== '') { |
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if ($this->path[0] === '/') { |
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// path-absolute (hier and relative) |
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// http:/my/path |
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// /my/path |
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if (strlen($this->path) >= 2 && $this->path[1] === '/') { |
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// This could happen if both the host gets stripped |
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// out |
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// http://my/path |
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// //my/path |
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$this->path = ''; |
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} else { |
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$this->path = $segments_encoder->encode($this->path); |
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} |
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} elseif (!is_null($this->scheme)) { |
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// path-rootless (hier) |
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// http:my/path |
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// Short circuit evaluation means we don't need to check nz |
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$this->path = $segments_encoder->encode($this->path); |
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} else { |
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// path-noscheme (relative) |
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// my/path |
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// (once again, not checking nz) |
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$segment_nc_encoder = new HTMLPurifier_PercentEncoder($chars_sub_delims . '@'); |
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$c = strpos($this->path, '/'); |
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if ($c !== false) { |
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$this->path = |
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$segment_nc_encoder->encode(substr($this->path, 0, $c)) . |
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$segments_encoder->encode(substr($this->path, $c)); |
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} else { |
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$this->path = $segment_nc_encoder->encode($this->path); |
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} |
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} |
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} else { |
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// path-empty (hier and relative) |
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$this->path = ''; // just to be safe |
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} |
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// qf = query and fragment |
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$qf_encoder = new HTMLPurifier_PercentEncoder($chars_pchar . '/?'); |
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if (!is_null($this->query)) { |
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$this->query = $qf_encoder->encode($this->query); |
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} |
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if (!is_null($this->fragment)) { |
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$this->fragment = $qf_encoder->encode($this->fragment); |
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} |
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return true; |
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} |
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/** |
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* Convert URI back to string |
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* @return string URI appropriate for output |
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*/ |
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public function toString() |
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{ |
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// reconstruct authority |
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$authority = null; |
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// there is a rendering difference between a null authority |
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// (http:foo-bar) and an empty string authority |
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// (http:///foo-bar). |
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if (!is_null($this->host)) { |
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$authority = ''; |
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if (!is_null($this->userinfo)) { |
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$authority .= $this->userinfo . '@'; |
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} |
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$authority .= $this->host; |
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if (!is_null($this->port)) { |
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$authority .= ':' . $this->port; |
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} |
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} |
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// Reconstruct the result |
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// One might wonder about parsing quirks from browsers after |
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// this reconstruction. Unfortunately, parsing behavior depends |
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// on what *scheme* was employed (file:///foo is handled *very* |
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// differently than http:///foo), so unfortunately we have to |
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// defer to the schemes to do the right thing. |
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$result = ''; |
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if (!is_null($this->scheme)) { |
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$result .= $this->scheme . ':'; |
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} |
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if (!is_null($authority)) { |
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$result .= '//' . $authority; |
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} |
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$result .= $this->path; |
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if (!is_null($this->query)) { |
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$result .= '?' . $this->query; |
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} |
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if (!is_null($this->fragment)) { |
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$result .= '#' . $this->fragment; |
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} |
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return $result; |
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} |
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/** |
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* Returns true if this URL might be considered a 'local' URL given |
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* the current context. This is true when the host is null, or |
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* when it matches the host supplied to the configuration. |
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* |
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* Note that this does not do any scheme checking, so it is mostly |
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* only appropriate for metadata that doesn't care about protocol |
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* security. isBenign is probably what you actually want. |
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* @param HTMLPurifier_Config $config |
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* @param HTMLPurifier_Context $context |
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* @return bool |
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*/ |
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public function isLocal($config, $context) |
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{ |
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if ($this->host === null) { |
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return true; |
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} |
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$uri_def = $config->getDefinition('URI'); |
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if ($uri_def->host === $this->host) { |
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return true; |
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} |
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return false; |
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} |
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/** |
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* Returns true if this URL should be considered a 'benign' URL, |
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* that is: |
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* |
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* - It is a local URL (isLocal), and |
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* - It has a equal or better level of security |
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* @param HTMLPurifier_Config $config |
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* @param HTMLPurifier_Context $context |
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* @return bool |
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*/ |
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public function isBenign($config, $context) |
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{ |
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if (!$this->isLocal($config, $context)) { |
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return false; |
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} |
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$scheme_obj = $this->getSchemeObj($config, $context); |
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if (!$scheme_obj) { |
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return false; |
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} // conservative approach |
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$current_scheme_obj = $config->getDefinition('URI')->getDefaultScheme($config, $context); |
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if ($current_scheme_obj->secure) { |
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if (!$scheme_obj->secure) { |
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return false; |
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} |
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} |
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return true; |
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} |
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} |
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// vim: et sw=4 sts=4 |
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