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HTML API: Ensure that NULL and whitespace-only CDATA sections don't f…
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…orbid FRAMESET.

When CDATA sections (which can only occur inside SVG and MathML content) consist only of NULL bytes or whitespace characters they should not clear the "frameset ok" flag. Previously they have always been clearing this flag, but in this patch the logic is updated to detect these sequences properly.

Developed in WordPress/wordpress-develop#7230
Discussed in https://core.trac.wordpress.org/ticket/61576

Follow-up to [58867].

Props dmsnell, jonsurrell.
See #61576.

Built from https://develop.svn.wordpress.org/trunk@58977


git-svn-id: http://core.svn.wordpress.org/trunk@58373 1a063a9b-81f0-0310-95a4-ce76da25c4cd
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@dmsnell
dmsnell committed Sep 3, 2024
1 parent 8d1fb4e commit 2ce04ce
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Showing 3 changed files with 63 additions and 64 deletions.
24 changes: 19 additions & 5 deletions wp-includes/html-api/class-wp-html-processor.php
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Original file line number Diff line number Diff line change
Expand Up @@ -843,10 +843,7 @@ public function step( $node_to_process = self::PROCESS_NEXT_NODE ): bool {

if ( self::PROCESS_NEXT_NODE === $node_to_process ) {
parent::next_token();
if (
WP_HTML_Tag_Processor::STATE_TEXT_NODE === $this->parser_state ||
WP_HTML_Tag_Processor::STATE_CDATA_NODE === $this->parser_state
) {
if ( WP_HTML_Tag_Processor::STATE_TEXT_NODE === $this->parser_state ) {
parent::subdivide_text_appropriately();
}
}
Expand Down Expand Up @@ -4375,7 +4372,6 @@ private function step_in_foreign_content(): bool {
}

switch ( $op ) {
case '#cdata-section':
case '#text':
/*
* > A character token that is U+0000 NULL
Expand All @@ -4395,6 +4391,24 @@ private function step_in_foreign_content(): bool {
$this->insert_foreign_element( $this->state->current_token, false );
return true;

/*
* CDATA sections are alternate wrappers for text content and therefore
* ought to follow the same rules as text nodes.
*/
case '#cdata-section':
/*
* NULL bytes and whitespace do not change the frameset-ok flag.
*/
$current_token = $this->bookmarks[ $this->state->current_token->bookmark_name ];
$cdata_content_start = $current_token->start + 9;
$cdata_content_length = $current_token->length - 12;
if ( strspn( $this->html, "\0 \t\n\f\r", $cdata_content_start, $cdata_content_length ) !== $cdata_content_length ) {
$this->state->frameset_ok = false;
}

$this->insert_foreign_element( $this->state->current_token, false );
return true;

/*
* > A comment token
*/
Expand Down
101 changes: 43 additions & 58 deletions wp-includes/html-api/class-wp-html-tag-processor.php
View file
Original file line number Diff line number Diff line change
Expand Up @@ -3337,8 +3337,8 @@ public function get_comment_type(): ?string {
}

/**
* Subdivides a matched text node or CDATA text node, splitting NULL byte sequences
* and decoded whitespace as distinct prefixes.
* Subdivides a matched text node, splitting NULL byte sequences and decoded whitespace as
* distinct nodes prefixes.
*
* Note that once anything that's neither a NULL byte nor decoded whitespace is
* encountered, then the remainder of the text node is left intact as generic text.
Expand Down Expand Up @@ -3368,70 +3368,55 @@ public function get_comment_type(): ?string {
* @return bool Whether the text node was subdivided.
*/
public function subdivide_text_appropriately(): bool {
if ( self::STATE_TEXT_NODE !== $this->parser_state ) {
return false;
}

$this->text_node_classification = self::TEXT_IS_GENERIC;

if ( self::STATE_TEXT_NODE === $this->parser_state ) {
/*
* NULL bytes are treated categorically different than numeric character
* references whose number is zero. `�` is not the same as `"\x00"`.
*/
$leading_nulls = strspn( $this->html, "\x00", $this->text_starts_at, $this->text_length );
if ( $leading_nulls > 0 ) {
$this->token_length = $leading_nulls;
$this->text_length = $leading_nulls;
$this->bytes_already_parsed = $this->token_starts_at + $leading_nulls;
$this->text_node_classification = self::TEXT_IS_NULL_SEQUENCE;
return true;
}
/*
* NULL bytes are treated categorically different than numeric character
* references whose number is zero. `�` is not the same as `"\x00"`.
*/
$leading_nulls = strspn( $this->html, "\x00", $this->text_starts_at, $this->text_length );
if ( $leading_nulls > 0 ) {
$this->token_length = $leading_nulls;
$this->text_length = $leading_nulls;
$this->bytes_already_parsed = $this->token_starts_at + $leading_nulls;
$this->text_node_classification = self::TEXT_IS_NULL_SEQUENCE;
return true;
}

/*
* Start a decoding loop to determine the point at which the
* text subdivides. This entails raw whitespace bytes and any
* character reference that decodes to the same.
*/
$at = $this->text_starts_at;
$end = $this->text_starts_at + $this->text_length;
while ( $at < $end ) {
$skipped = strspn( $this->html, " \t\f\r\n", $at, $end - $at );
$at += $skipped;

if ( $at < $end && '&' === $this->html[ $at ] ) {
$matched_byte_length = null;
$replacement = WP_HTML_Decoder::read_character_reference( 'data', $this->html, $at, $matched_byte_length );
if ( isset( $replacement ) && 1 === strspn( $replacement, " \t\f\r\n" ) ) {
$at += $matched_byte_length;
continue;
}
/*
* Start a decoding loop to determine the point at which the
* text subdivides. This entails raw whitespace bytes and any
* character reference that decodes to the same.
*/
$at = $this->text_starts_at;
$end = $this->text_starts_at + $this->text_length;
while ( $at < $end ) {
$skipped = strspn( $this->html, " \t\f\r\n", $at, $end - $at );
$at += $skipped;

if ( $at < $end && '&' === $this->html[ $at ] ) {
$matched_byte_length = null;
$replacement = WP_HTML_Decoder::read_character_reference( 'data', $this->html, $at, $matched_byte_length );
if ( isset( $replacement ) && 1 === strspn( $replacement, " \t\f\r\n" ) ) {
$at += $matched_byte_length;
continue;
}

break;
}

if ( $at > $this->text_starts_at ) {
$new_length = $at - $this->text_starts_at;
$this->text_length = $new_length;
$this->token_length = $new_length;
$this->bytes_already_parsed = $at;
$this->text_node_classification = self::TEXT_IS_WHITESPACE;
return true;
}

return false;
break;
}

// Unlike text nodes, there are no character references within CDATA sections.
if ( self::STATE_CDATA_NODE === $this->parser_state ) {
$leading_nulls = strspn( $this->html, "\x00", $this->text_starts_at, $this->text_length );
if ( $leading_nulls === $this->text_length ) {
$this->text_node_classification = self::TEXT_IS_NULL_SEQUENCE;
return true;
}

$leading_ws = strspn( $this->html, " \t\f\r\n", $this->text_starts_at, $this->text_length );
if ( $leading_ws === $this->text_length ) {
$this->text_node_classification = self::TEXT_IS_WHITESPACE;
return true;
}
if ( $at > $this->text_starts_at ) {
$new_length = $at - $this->text_starts_at;
$this->text_length = $new_length;
$this->token_length = $new_length;
$this->bytes_already_parsed = $at;
$this->text_node_classification = self::TEXT_IS_WHITESPACE;
return true;
}

return false;
Expand Down
2 changes: 1 addition & 1 deletion wp-includes/version.php
View file
Original file line number Diff line number Diff line change
Expand Up @@ -16,7 +16,7 @@
*
* @global string $wp_version
*/
$wp_version = '6.7-alpha-58976';
$wp_version = '6.7-alpha-58977';

/**
* Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.
Expand Down

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