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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 | ||
f4f0f80d | 37 | $uri = $this->expandCSSEscape($uri); |
f45a286b AD |
38 | |
39 | $result = parent::validate($uri, $config, $context); | |
40 | ||
41 | if ($result === false) return false; | |
42 | ||
f4f0f80d AD |
43 | // extra sanity check; should have been done by URI |
44 | $result = str_replace(array('"', "\\", "\n", "\x0c", "\r"), "", $result); | |
f45a286b | 45 | |
f4f0f80d AD |
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\")"; | |
f45a286b AD |
56 | |
57 | } | |
58 | ||
59 | } | |
60 | ||
61 | // vim: et sw=4 sts=4 |