1: <?php
2:
3: /**
4: * Validates a URI in CSS syntax, which uses url('http://example.com')
5: * @note While theoretically speaking a URI in a CSS document could
6: * be non-embedded, as of CSS2 there is no such usage so we're
7: * generalizing it. This may need to be changed in the future.
8: * @warning Since HTMLPurifier_AttrDef_CSS blindly uses semicolons as
9: * the separator, you cannot put a literal semicolon in
10: * in the URI. Try percent encoding it, in that case.
11: */
12: class HTMLPurifier_AttrDef_CSS_URI extends HTMLPurifier_AttrDef_URI
13: {
14:
15: public function __construct() {
16: parent::__construct(true); // always embedded
17: }
18:
19: public function validate($uri_string, $config, $context) {
20: // parse the URI out of the string and then pass it onto
21: // the parent object
22:
23: $uri_string = $this->parseCDATA($uri_string);
24: if (strpos($uri_string, 'url(') !== 0) return false;
25: $uri_string = substr($uri_string, 4);
26: $new_length = strlen($uri_string) - 1;
27: if ($uri_string[$new_length] != ')') return false;
28: $uri = trim(substr($uri_string, 0, $new_length));
29:
30: if (!empty($uri) && ($uri[0] == "'" || $uri[0] == '"')) {
31: $quote = $uri[0];
32: $new_length = strlen($uri) - 1;
33: if ($uri[$new_length] !== $quote) return false;
34: $uri = substr($uri, 1, $new_length - 1);
35: }
36:
37: $uri = $this->expandCSSEscape($uri);
38:
39: $result = parent::validate($uri, $config, $context);
40:
41: if ($result === false) return false;
42:
43: // extra sanity check; should have been done by URI
44: $result = str_replace(array('"', "\\", "\n", "\x0c", "\r"), "", $result);
45:
46: // suspicious characters are ()'; we're going to percent encode
47: // them for safety.
48: $result = str_replace(array('(', ')', "'"), array('%28', '%29', '%27'), $result);
49:
50: // there's an extra bug where ampersands lose their escaping on
51: // an innerHTML cycle, so a very unlucky query parameter could
52: // then change the meaning of the URL. Unfortunately, there's
53: // not much we can do about that...
54:
55: return "url(\"$result\")";
56:
57: }
58:
59: }
60:
61: // vim: et sw=4 sts=4
62: