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|
<?php
/**
* Validates a font family list according to CSS spec
* @todo whitelisting allowed fonts would be nice
*/
class HTMLPurifier_AttrDef_CSS_FontFamily extends HTMLPurifier_AttrDef
{
public function validate($string, $config, $context) {
static $generic_names = array(
'serif' => true,
'sans-serif' => true,
'monospace' => true,
'fantasy' => true,
'cursive' => true
);
// assume that no font names contain commas in them
$fonts = explode(',', $string);
$final = '';
foreach($fonts as $font) {
$font = trim($font);
if ($font === '') continue;
// match a generic name
if (isset($generic_names[$font])) {
$final .= $font . ', ';
continue;
}
// match a quoted name
if ($font[0] === '"' || $font[0] === "'") {
$length = strlen($font);
if ($length <= 2) continue;
$quote = $font[0];
if ($font[$length - 1] !== $quote) continue;
$font = substr($font, 1, $length - 2);
$new_font = '';
for ($i = 0, $c = strlen($font); $i < $c; $i++) {
if ($font[$i] === '\\') {
$i++;
if ($i >= $c) {
$new_font .= '\\';
break;
}
if (ctype_xdigit($font[$i])) {
$code = $font[$i];
for ($a = 1, $i++; $i < $c && $a < 6; $i++, $a++) {
if (!ctype_xdigit($font[$i])) break;
$code .= $font[$i];
}
// We have to be extremely careful when adding
// new characters, to make sure we're not breaking
// the encoding.
$char = HTMLPurifier_Encoder::unichr(hexdec($code));
if (HTMLPurifier_Encoder::cleanUTF8($char) === '') continue;
$new_font .= $char;
if ($i < $c && trim($font[$i]) !== '') $i--;
continue;
}
if ($font[$i] === "\n") continue;
}
$new_font .= $font[$i];
}
$font = $new_font;
}
// $font is a pure representation of the font name
if (ctype_alnum($font) && $font !== '') {
// very simple font, allow it in unharmed
$final .= $font . ', ';
continue;
}
// complicated font, requires quoting
// armor single quotes and new lines
$font = str_replace("\\", "\\\\", $font);
$font = str_replace("'", "\\'", $font);
$final .= "'$font', ";
}
$final = rtrim($final, ', ');
if ($final === '') return false;
return $final;
}
}
// vim: et sw=4 sts=4
|
