nested `var()` values, and assigning values to CSS variables. * Added support for `object-fit`, `gap`, `column-gap`, `row-gap`, and `flex-wrap`. * Extended `margin-*` and `padding-*` support for logical properties. * @since 6.2.0 Added support for `aspect-ratio`, `position`, `top`, `right`, `bottom`, `left`, * and `z-index` CSS properties. * @since 6.3.0 Extended support for `filter` to accept a URL and added support for repeat(). * Added support for `box-shadow`. * @since 6.4.0 Added support for `writing-mode`. * * @param string $css A string of CSS rules. * @param string $deprecated Not used. * @return string Filtered string of CSS rules. */ function safecss_filter_attr( $css, $deprecated = '' ) { if ( ! empty( $deprecated ) ) { _deprecated_argument( __FUNCTION__, '2.8.1' ); // Never implemented. } $css = wp_kses_no_null( $css ); $css = str_replace( array( "\n", "\r", "\t" ), '', $css ); $allowed_protocols = wp_allowed_protocols(); $css_array = explode( ';', trim( $css ) ); /** * Filters the list of allowed CSS attributes. * * @since 2.8.1 * * @param string[] $attr Array of allowed CSS attributes. */ $allowed_attr = apply_filters( 'safe_style_css', array( 'background', 'background-color', 'background-image', 'background-position', 'background-size', 'background-attachment', 'background-blend-mode', 'border', 'border-radius', 'border-width', 'border-color', 'border-style', 'border-right', 'border-right-color', 'border-right-style', 'border-right-width', 'border-bottom', 'border-bottom-color', 'border-bottom-left-radius', 'border-bottom-right-radius', 'border-bottom-style', 'border-bottom-width', 'border-bottom-right-radius', 'border-bottom-left-radius', 'border-left', 'border-left-color', 'border-left-style', 'border-left-width', 'border-top', 'border-top-color', 'border-top-left-radius', 'border-top-right-radius', 'border-top-style', 'border-top-width', 'border-top-left-radius', 'border-top-right-radius', 'border-spacing', 'border-collapse', 'caption-side', 'columns', 'column-count', 'column-fill', 'column-gap', 'column-rule', 'column-span', 'column-width', 'color', 'filter', 'font', 'font-family', 'font-size', 'font-style', 'font-variant', 'font-weight', 'letter-spacing', 'line-height', 'text-align', 'text-decoration', 'text-indent', 'text-transform', 'height', 'min-height', 'max-height', 'width', 'min-width', 'max-width', 'margin', 'margin-right', 'margin-bottom', 'margin-left', 'margin-top', 'margin-block-start', 'margin-block-end', 'margin-inline-start', 'margin-inline-end', 'padding', 'padding-right', 'padding-bottom', 'padding-left', 'padding-top', 'padding-block-start', 'padding-block-end', 'padding-inline-start', 'padding-inline-end', 'flex', 'flex-basis', 'flex-direction', 'flex-flow', 'flex-grow', 'flex-shrink', 'flex-wrap', 'gap', 'column-gap', 'row-gap', 'grid-template-columns', 'grid-auto-columns', 'grid-column-start', 'grid-column-end', 'grid-column-gap', 'grid-template-rows', 'grid-auto-rows', 'grid-row-start', 'grid-row-end', 'grid-row-gap', 'grid-gap', 'justify-content', 'justify-items', 'justify-self', 'align-content', 'align-items', 'align-self', 'clear', 'cursor', 'direction', 'float', 'list-style-type', 'object-fit', 'object-position', 'overflow', 'vertical-align', 'writing-mode', 'position', 'top', 'right', 'bottom', 'left', 'z-index', 'box-shadow', 'aspect-ratio', // Custom CSS properties. '--*', ) ); /* * CSS attributes that accept URL data types. * * This is in accordance to the CSS spec and unrelated to * the sub-set of supported attributes above. * * See: https://developer.mozilla.org/en-US/docs/Web/CSS/url */ $css_url_data_types = array( 'background', 'background-image', 'cursor', 'filter', 'list-style', 'list-style-image', ); /* * CSS attributes that accept gradient data types. * */ $css_gradient_data_types = array( 'background', 'background-image', ); if ( empty( $allowed_attr ) ) { return $css; } $css = ''; foreach ( $css_array as $css_item ) { if ( '' === $css_item ) { continue; } $css_item = trim( $css_item ); $css_test_string = $css_item; $found = false; $url_attr = false; $gradient_attr = false; $is_custom_var = false; if ( ! str_contains( $css_item, ':' ) ) { $found = true; } else { $parts = explode( ':', $css_item, 2 ); $css_selector = trim( $parts[0] ); // Allow assigning values to CSS variables. if ( in_array( '--*', $allowed_attr, true ) && preg_match( '/^--[a-zA-Z0-9-_]+$/', $css_selector ) ) { $allowed_attr[] = $css_selector; $is_custom_var = true; } if ( in_array( $css_selector, $allowed_attr, true ) ) { $found = true; $url_attr = in_array( $css_selector, $css_url_data_types, true ); $gradient_attr = in_array( $css_selector, $css_gradient_data_types, true ); } if ( $is_custom_var ) { $css_value = trim( $parts[1] ); $url_attr = str_starts_with( $css_value, 'url(' ); $gradient_attr = str_contains( $css_value, '-gradient(' ); } } if ( $found && $url_attr ) { // Simplified: matches the sequence `url(*)`. preg_match_all( '/url\([^)]+\)/', $parts[1], $url_matches ); foreach ( $url_matches[0] as $url_match ) { // Clean up the URL from each of the matches above. preg_match( '/^url\(\s*([\'\"]?)(.*)(\g1)\s*\)$/', $url_match, $url_pieces ); if ( empty( $url_pieces[2] ) ) { $found = false; break; } $url = trim( $url_pieces[2] ); if ( empty( $url ) || wp_kses_bad_protocol( $url, $allowed_protocols ) !== $url ) { $found = false; break; } else { // Remove the whole `url(*)` bit that was matched above from the CSS. $css_test_string = str_replace( $url_match, '', $css_test_string ); } } } if ( $found && $gradient_attr ) { $css_value = trim( $parts[1] ); if ( preg_match( '/^(repeating-)?(linear|radial|conic)-gradient\(([^()]|rgb[a]?\([^()]*\))*\)$/', $css_value ) ) { // Remove the whole `gradient` bit that was matched above from the CSS. $css_test_string = str_replace( $css_value, '', $css_test_string ); } } if ( $found ) { /* * Allow CSS functions like var(), calc(), etc. by removing them from the test string. * Nested functions and parentheses are also removed, so long as the parentheses are balanced. */ $css_test_string = preg_replace( '/\b(?:var|calc|min|max|minmax|clamp|repeat)(\((?:[^()]|(?1))*\))/', '', $css_test_string ); /* * Disallow CSS containing \ ( & } = or comments, except for within url(), var(), calc(), etc. * which were removed from the test string above. */ $allow_css = ! preg_match( '%[\\\(&=}]|/\*%', $css_test_string ); /** * Filters the check for unsafe CSS in `safecss_filter_attr`. * * Enables developers to determine whether a section of CSS should be allowed or discarded. * By default, the value will be false if the part contains \ ( & } = or comments. * Return true to allow the CSS part to be included in the output. * * @since 5.5.0 * * @param bool $allow_css Whether the CSS in the test string is considered safe. * @param string $css_test_string The CSS string to test. */ $allow_css = apply_filters( 'safecss_filter_attr_allow_css', $allow_css, $css_test_string ); // Only add the CSS part if it passes the regex check. if ( $allow_css ) { if ( '' !== $css ) { $css .= ';'; } $css .= $css_item; } } } return $css; } /** * Helper function to add global attributes to a tag in the allowed HTML list. * * @since 3.5.0 * @since 5.0.0 Added support for `data-*` wildcard attributes. * @since 6.0.0 Added `dir`, `lang`, and `xml:lang` to global attributes. * @since 6.3.0 Added `aria-controls`, `aria-current`, and `aria-expanded` attributes. * @since 6.4.0 Added `aria-live` and `hidden` attributes. * * @access private * @ignore * * @param array $value An array of attributes. * @return array The array of attributes with global attributes added. */ function _wp_add_global_attributes( $value ) { $global_attributes = array( 'aria-controls' => true, 'aria-current' => true, 'aria-describedby' => true, 'aria-details' => true, 'aria-expanded' => true, 'aria-hidden' => true, 'aria-label' => true, 'aria-labelledby' => true, 'aria-live' => true, 'class' => true, 'data-*' => true, 'dir' => true, 'hidden' => true, 'id' => true, 'lang' => true, 'style' => true, 'title' => true, 'role' => true, 'xml:lang' => true, ); if ( true === $value ) { $value = array(); } if ( is_array( $value ) ) { return array_merge( $value, $global_attributes ); } return $value; } /** * Helper function to check if this is a safe PDF URL. * * @since 5.9.0 * @access private * @ignore * * @param string $url The URL to check. * @return bool True if the URL is safe, false otherwise. */ function _wp_kses_allow_pdf_objects( $url ) { // We're not interested in URLs that contain query strings or fragments. if ( str_contains( $url, '?' ) || str_contains( $url, '#' ) ) { return false; } // If it doesn't have a PDF extension, it's not safe. if ( ! str_ends_with( $url, '.pdf' ) ) { return false; } // If the URL host matches the current site's media URL, it's safe. $upload_info = wp_upload_dir( null, false ); $parsed_url = wp_parse_url( $upload_info['url'] ); $upload_host = isset( $parsed_url['host'] ) ? $parsed_url['host'] : ''; $upload_port = isset( $parsed_url['port'] ) ? ':' . $parsed_url['port'] : ''; if ( str_starts_with( $url, "http://$upload_host$upload_port/" ) || str_starts_with( $url, "https://$upload_host$upload_port/" ) ) { return true; } return false; }