1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
|
<?php
require_once("MTUtil.php");
function sanitize($s, $arg) {
if (($arg) && (!is_array($arg)))
$arg = sanitize_parse_spec($arg);
$ok_tags = $arg['ok'];
$tag_attr = $arg['tag_attr'];
$s = preg_replace('/\x00/', '', $s);
$closings = array('<'.'?' => '?'.'>', '<!--' => '-->', '<%' => '%>');
$tokens = preg_split('/(<(?:!--|%|\?)|<\/\w*|<\w*|(?:-->|%>|\?'.'>|>))/', $s, -1, PREG_SPLIT_DELIM_CAPTURE);
$open_tag_a = array();
$open_tag_h = array();
$toknum = 0;
$result = '';
while ($toknum < count($tokens)) {
$token = $tokens[$toknum];
if (isset($closings[$token])) {
$toknum = sanitize_tokens_up_to($tokens, $toknum, $closings[$token]);
} elseif (substr($token, 0, 1) == '<') {
$closure = 0;
$name = strtolower(substr($token, 1));
$start = $toknum;
$end = sanitize_tokens_up_to($tokens, $start, '>');
$toknum = $end;
if (substr($name, 0, 1) == '/') {
$name = substr($name, 1);
$closure = 1;
}
if (isset($ok_tags[$name])) {
if ($tag_attr[$name] == '/')
$closure = 2;
# process attribute list...
$inside = sanitize_output_tokens($tokens, $start + 1, $end - 1);
if (preg_match('!/>$!', $inside))
$closure = 2;
$inside = preg_replace('!/?>$!', '', $inside);
$attrs = '';
if (preg_match_all('/\s*(\w+)\s*=(?:([\'"])(.*?)\2|([^\s]+))\s*/s', $inside, $matches, PREG_SET_ORDER)) {
foreach ($matches as $match) {
$attr = strtolower($match[1]);
if (isset($match[4])) {
$value = $match[4];
$value = '"' . preg_replace('/"/', '"', $value) . '"';
$dec_val = decode_html($match[4]);
} else {
$value = $match[2] . $match[3] . $match[2];
$dec_val = decode_html($match[3]);
}
if (isset($ok_tags[$name][$attr]) ||
isset($ok_tags['*'][$attr])) {
$safe = 1;
if (preg_match('/^(src|href|dynsrc)$/', $attr)) {
$dec_val = preg_replace('/�*58(?:=;|[^0-9])/', ':', $dec_val);
$dec_val = preg_replace('/�*3[Aa](?:=;|[^a-fA-F0-9])/', ':', $dec_val);
if (preg_match('/^([\s\S]+?):/', $dec_val, $proto_match)) {
$proto = $proto_match[1];
if (preg_match('/[\r\n\t]/', $proto)) {
$safe = 0;
} else {
$proto = preg_replace('/\s+/s', '', $proto);
if (preg_match('/[^a-zA-Z0-9\\+]/', $proto))
$safe = 0;
elseif (preg_match('/script$/i', $proto))
$safe = 0;
}
}
}
if ($safe)
$attrs .= ' ' . $attr . '=' . $value;
}
}
}
if (($closure != 1) || ($closure == 1 && isset($open_tag_h[$name]))) {
if ($closure == 1) {
$result .= sanitize_expel_up_to($open_tag_a, $open_tag_h, $name);
} elseif (!$closure) {
$open_tag_a[] = $name;
$open_tag_h[$name]++;
}
}
$result .= '<' .
($closure == 1 ? '/' : '') .
$name .
$attrs .
($closure == 2 ? ' /' : '') . '>';
if ($closure == 1)
$open_tag_h[$name]--;
}
} else {
if (strlen($token) > 0)
$result .= $token;
$toknum++;
}
}
$result .= sanitize_expel_up_to($open_tag_a, $open_tag_h, null);
return $result;
}
function sanitize_parse_spec($a) {
$ok_tags = array();
$tag_attr = array();
$rules = preg_split('/\s*,\s*/', $a);
foreach ($rules as $rule) {
$ok_attr = array();
$tag = strtolower($rule);
$style = '';
if (preg_match('|^([^\s]+)\s+(.+)$|', $tag, $matches)) {
$tag = $matches[1];
$attrs = $matches[2];
if (preg_match('!/$!', $tag)) {
$tag = substr($tag, 0, strlen($tag) - 1);
$style = '/';
}
$a_attr = preg_split('/\s+/', $attrs);
foreach ($a_attr as $attr) {
$ok_attr[$attr] = 1;
}
} else {
if (preg_match('!/$!', $tag)) {
$tag = substr($tag, 0, strlen($tag) - 1);
$style = '/';
}
}
if ($style) $tag_attr[$tag] = $style;
$ok_tags[$tag] = count($ok_attr) ? $ok_attr : 1;
}
return array('ok' => $ok_tags, 'tag_attr' => $tag_attr);
}
function sanitize_expel_up_to(&$open_tag_a, &$open_tag_h, $stop_tag) {
$out = '';
while (count($open_tag_a) &&
(empty($stop_tag) || $open_tag_a[count($open_tag_a)-1] != $stop_tag)) {
$t = array_pop($open_tag_a);
$open_tag_h[$t]--;
$out .= '</' . $t . '>';
}
if (count($open_tag_a))
$t = array_pop($open_tag_a);
return $out;
}
function sanitize_tokens_up_to($tokens, $i, $closure) {
while ($i < count($tokens)) {
if ($tokens[$i++] == $closure)
break;
}
return $i;
}
function sanitize_output_tokens($tokens, $start, $end) {
$out = '';
for ($i = $start; $i <= $end; $i++)
$out .= $tokens[$i];
return $out;
}
?>
|
