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<?php
/**
* Validates a host according to the IPv4, IPv6 and DNS (future) specifications.
*/
class HTMLPurifier_AttrDef_URI_Host extends HTMLPurifier_AttrDef
{
/**
* IPv4 sub-validator.
* @type HTMLPurifier_AttrDef_URI_IPv4
*/
protected $ipv4;
/**
* IPv6 sub-validator.
* @type HTMLPurifier_AttrDef_URI_IPv6
*/
protected $ipv6;
public function __construct()
{
$this->ipv4 = new HTMLPurifier_AttrDef_URI_IPv4();
$this->ipv6 = new HTMLPurifier_AttrDef_URI_IPv6();
}
/**
* @param string $string
* @param HTMLPurifier_Config $config
* @param HTMLPurifier_Context $context
* @return bool|string
*/
public function validate($string, $config, $context)
{
$length = strlen($string);
// empty hostname is OK; it's usually semantically equivalent:
// the default host as defined by a URI scheme is used:
//
// If the URI scheme defines a default for host, then that
// default applies when the host subcomponent is undefined
// or when the registered name is empty (zero length).
if ($string === '') {
return '';
}
if ($length > 1 && $string[0] === '[' && $string[$length - 1] === ']') {
//IPv6
$ip = substr($string, 1, $length - 2);
$valid = $this->ipv6->validate($ip, $config, $context);
if ($valid === false) {
return false;
}
return '[' . $valid . ']';
}
// need to do checks on unusual encodings too
$ipv4 = $this->ipv4->validate($string, $config, $context);
if ($ipv4 !== false) {
return $ipv4;
}
// A regular domain name.
// This doesn't match I18N domain names, but we don't have proper IRI support,
// so force users to insert Punycode.
// There is not a good sense in which underscores should be
// allowed, since it's technically not! (And if you go as
// far to allow everything as specified by the DNS spec...
// well, that's literally everything, modulo some space limits
// for the components and the overall name (which, by the way,
// we are NOT checking!). So we (arbitrarily) decide this:
// let's allow underscores wherever we would have allowed
// hyphens, if they are enabled. This is a pretty good match
// for browser behavior, for example, a large number of browsers
// cannot handle foo_.example.com, but foo_bar.example.com is
// fairly well supported.
$underscore = $config->get('Core.AllowHostnameUnderscore') ? '_' : '';
// Based off of RFC 1738, but amended so that
// as per RFC 3696, the top label need only not be all numeric.
// The productions describing this are:
$a = '[a-z]'; // alpha
$an = '[a-z0-9]'; // alphanum
$and = "[a-z0-9-$underscore]"; // alphanum | "-"
// domainlabel = alphanum | alphanum *( alphanum | "-" ) alphanum
$domainlabel = "$an(?:$and*$an)?";
// AMENDED as per RFC 3696
// toplabel = alphanum | alphanum *( alphanum | "-" ) alphanum
// side condition: not all numeric
$toplabel = "$an(?:$and*$an)?";
// hostname = *( domainlabel "." ) toplabel [ "." ]
if (preg_match("/^(?:$domainlabel\.)*($toplabel)\.?$/i", $string, $matches)) {
if (!ctype_digit($matches[1])) {
return $string;
}
}
// PHP 5.3 and later support this functionality natively
if (function_exists('idn_to_ascii')) {
if (defined('IDNA_NONTRANSITIONAL_TO_ASCII') && defined('INTL_IDNA_VARIANT_UTS46')) {
$string = idn_to_ascii($string, IDNA_NONTRANSITIONAL_TO_ASCII, INTL_IDNA_VARIANT_UTS46);
} else {
$string = idn_to_ascii($string);
}
// If we have Net_IDNA2 support, we can support IRIs by
// punycoding them. (This is the most portable thing to do,
// since otherwise we have to assume browsers support
} elseif ($config->get('Core.EnableIDNA') && class_exists('Net_IDNA2')) {
$idna = new Net_IDNA2(array('encoding' => 'utf8', 'overlong' => false, 'strict' => true));
// we need to encode each period separately
$parts = explode('.', $string);
try {
$new_parts = array();
foreach ($parts as $part) {
$encodable = false;
for ($i = 0, $c = strlen($part); $i < $c; $i++) {
if (ord($part[$i]) > 0x7a) {
$encodable = true;
break;
}
}
if (!$encodable) {
$new_parts[] = $part;
} else {
$new_parts[] = $idna->encode($part);
}
}
$string = implode('.', $new_parts);
} catch (Exception $e) {
// XXX error reporting
}
}
// Try again
if (preg_match("/^($domainlabel\.)*$toplabel\.?$/i", $string)) {
return $string;
}
return false;
}
}
// vim: et sw=4 sts=4
|
