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Fix: Prevent infinite loop in Tag Processor in certain truncated documents #45537

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merged 1 commit into from
Nov 4, 2022
Merged

Fix: Prevent infinite loop in Tag Processor in certain truncated documents #45537

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45 changes: 36 additions & 9 deletions lib/experimental/html/class-wp-html-tag-processor.php
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Original file line number Diff line number Diff line change
Expand Up @@ -445,7 +445,7 @@ private function skip_rcdata( $tag_name ) {

$at = $this->parsed_bytes;

while ( true ) {
while ( false !== $at && $at < $doc_length ) {
$at = strpos( $this->html, '</', $at );

// If we have no possible tag closer then fail.
Expand Down Expand Up @@ -494,6 +494,8 @@ private function skip_rcdata( $tag_name ) {
return;
}
}

return false;
}

/**
Expand All @@ -507,7 +509,7 @@ private function skip_script_data() {
$doc_length = strlen( $html );
$at = $this->parsed_bytes;

while ( $at < $doc_length ) {
while ( false !== $at && $at < $doc_length ) {
$at += strcspn( $html, '-<', $at );

/*
Expand Down Expand Up @@ -613,6 +615,8 @@ private function skip_script_data() {

++$at;
}

return false;
}

/**
Expand All @@ -623,10 +627,11 @@ private function skip_script_data() {
private function parse_next_tag() {
$this->after_tag();

$html = $this->html;
$at = $this->parsed_bytes;
$html = $this->html;
$doc_length = strlen( $html );
$at = $this->parsed_bytes;

while ( true ) {
while ( false !== $at && $at < $doc_length ) {
$at = strpos( $html, '<', $at );
if ( false === $at ) {
return false;
Expand Down Expand Up @@ -663,7 +668,12 @@ private function parse_next_tag() {
'-' === $html[ $at + 2 ] &&
'-' === $html[ $at + 3 ]
) {
$at = strpos( $html, '-->', $at + 4 ) + 3;
$closer_at = strpos( $html, '-->', $at + 4 );
if ( false === $closer_at ) {
return false;
}

$at = $closer_at + 3;
continue;
}

Expand All @@ -680,7 +690,12 @@ private function parse_next_tag() {
'A' === $html[ $at + 7 ] &&
'[' === $html[ $at + 8 ]
) {
$at = strpos( $html, ']]>', $at + 9 ) + 3;
$closer_at = strpos( $html, ']]>', $at + 9 );
if ( false === $closer_at ) {
return false;
}

$at = $closer_at + 3;
continue;
}

Expand All @@ -699,7 +714,12 @@ private function parse_next_tag() {
'P' === strtoupper( $html[ $at + 7 ] ) &&
'E' === strtoupper( $html[ $at + 8 ] )
) {
$at = strpos( $html, '>', $at + 9 ) + 1;
$closer_at = strpos( $html, '>', $at + 9 );
if ( false === $closer_at ) {
return false;
}

$at = $closer_at + 1;
continue;
}

Expand All @@ -716,12 +736,19 @@ private function parse_next_tag() {
* https://html.spec.whatwg.org/multipage/parsing.html#tag-open-state
*/
if ( '?' === $html[ $at + 1 ] ) {
$at = strpos( $html, '>', $at + 2 ) + 1;
$closer_at = strpos( $html, '>', $at + 2 );
if ( false === $closer_at ) {
return false;
}

$at = $closer_at + 1;
continue;
}

++$at;
}

return false;
}

/**
Expand Down