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strip tab in attribute value to block tabbed data:text/html uri #93

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strip tab in attribute value to block tabbed data:text/html uri #93

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13 changes: 13 additions & 0 deletions Tests/InputFilterTest.php
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Original file line number Diff line number Diff line change
Expand Up @@ -2048,4 +2048,17 @@ public function testCleanObject()

$this->assertEquals($expected, $filter->clean($object));
}

/**
* A tab inside the scheme must not slip a data:text/html URI past the attribute filter,
* as browsers strip tab/newline characters when parsing a URL.
*/
public function testCleanStripsTabbedHtmlDataUri()
{
$filter = new InputFilter(['a'], ['href']);

$input = "<a href=\"data:text/\thtml;base64,PHNjcmlwdD5hbGVydCgxKTwvc2NyaXB0Pg==\">Data link</a>";

$this->assertSame('<a>Data link</a>', $filter->clean($input, 'html'));
}
}
4 changes: 2 additions & 2 deletions src/InputFilter.php
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Original file line number Diff line number Diff line change
Expand Up @@ -388,7 +388,7 @@
*/
if (
(!preg_match('/^[a-z][a-z0-9]*$/i', $tagName))
|| (!$tagName)

Check failure on line 391 in src/InputFilter.php

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GitHub Actions / framework-ci / Run PHPstan 

Negated boolean expression is always false.
|| ((\in_array(strtolower($tagName), $this->blockedTags)) && $this->xssAuto)
) {
$postTag = substr($postTag, ($tagLength + 2));
Expand Down Expand Up @@ -586,8 +586,8 @@
// Strips unicode, hex, etc
$attrSubSet[1] = str_replace('&#', '', $attrSubSet[1]);

// Strip normal newline within attr value
$attrSubSet[1] = preg_replace('/[\n\r]/', '', $attrSubSet[1]);
// Strip tab and newline within attr value (browsers drop these when parsing a URL)
$attrSubSet[1] = preg_replace('/[\t\n\r]/', '', $attrSubSet[1]);

// Strip double quotes
$attrSubSet[1] = str_replace('"', '', $attrSubSet[1]);
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