Changeset 59515

Timestamp:

12/14/2024 11:51:09 PM (20 months ago)

Author:

SergeyBiryukov

Message:

Formatting: Check the result of preg_split() in convert_smilies().

This aims to avoid a fatal error from count() when preg_split() fails on large input.

Includes:

• Optimizing the regular expression used to split the input by tags to avoid unlimited backtracking for better performance.
• Adjusting the function logic for better readability.

Follow-up to [340], [4380], [26191].

Props podpirate, nathkrill, rajinsharwar, dmsnell, bjorsch, q0rban, audrasjb, rupw, Ov3rfly, jorbin, nhrrob, chaion07, mcqueen22, azaozz, narenin, roybellingan, SergeyBiryukov.
See #51019.

Location:

trunk

Files:

• src/wp-includes/formatting.php (modified) (1 diff)
• tests/phpunit/tests/formatting/convertSmilies.php (modified) (1 diff)

trunk/src/wp-includes/formatting.php

@@ -3474 +3474 @@
 function convert_smilies( $text ) {
         global $wp_smiliessearch;
+
+        if ( ! get_option( 'use_smilies' ) || empty( $wp_smiliessearch ) ) {
+                // Return default text.
+                return $text;
+        }
+
+        // HTML loop taken from texturize function, could possible be consolidated.
+        $textarr = preg_split( '/(<[^>]*>)/U', $text, -1, PREG_SPLIT_DELIM_CAPTURE ); // Capture the tags as well as in between.
+
+        if ( false === $textarr ) {
+                // Return default text.
+                return $text;
+        }
+
+        // Loop stuff.
+        $stop   = count( $textarr );
         $output = '';
-        if ( get_option( 'use_smilies' ) && ! empty( $wp_smiliessearch ) ) {
-                // HTML loop taken from texturize function, could possible be consolidated.
-                $textarr = preg_split( '/(<.*>)/U', $text, -1, PREG_SPLIT_DELIM_CAPTURE ); // Capture the tags as well as in between.
-                $stop    = count( $textarr ); // Loop stuff.
-
-                // Ignore processing of specific tags.
-                $tags_to_ignore       = 'code|pre|style|script|textarea';
-                $ignore_block_element = '';
-
-                for ( $i = 0; $i < $stop; $i++ ) {
-                        $content = $textarr[ $i ];
-
-                        // If we're in an ignore block, wait until we find its closing tag.
-                        if ( '' === $ignore_block_element && preg_match( '/^<(' . $tags_to_ignore . ')[^>]*>/', $content, $matches ) ) {
-                                $ignore_block_element = $matches[1];
-                        }
-
-                        // If it's not a tag and not in ignore block.
-                        if ( '' === $ignore_block_element && strlen( $content ) > 0 && '<' !== $content[0] ) {
-                                $content = preg_replace_callback( $wp_smiliessearch, 'translate_smiley', $content );
-                        }
-
-                        // Did we exit ignore block?
-                        if ( '' !== $ignore_block_element && '</' . $ignore_block_element . '>' === $content ) {
-                                $ignore_block_element = '';
-                        }
-
-                        $output .= $content;
-                }
-        } else {
-                // Return default text.
-                $output = $text;
-        }
+
+        // Ignore processing of specific tags.
+        $tags_to_ignore       = 'code|pre|style|script|textarea';
+        $ignore_block_element = '';
+
+        for ( $i = 0; $i < $stop; $i++ ) {
+                $content = $textarr[ $i ];
+
+                // If we're in an ignore block, wait until we find its closing tag.
+                if ( '' === $ignore_block_element && preg_match( '/^<(' . $tags_to_ignore . ')[^>]*>/', $content, $matches ) ) {
+                        $ignore_block_element = $matches[1];
+                }
+
+                // If it's not a tag and not in ignore block.
+                if ( '' === $ignore_block_element && strlen( $content ) > 0 && '<' !== $content[0] ) {
+                        $content = preg_replace_callback( $wp_smiliessearch, 'translate_smiley', $content );
+                }
+
+                // Did we exit ignore block?
+                if ( '' !== $ignore_block_element && '</' . $ignore_block_element . '>' === $content ) {
+                        $ignore_block_element = '';
+                }
+
+                $output .= $content;
+        }
+
         return $output;
 }

trunk/tests/phpunit/tests/formatting/convertSmilies.php

@@ -394 +394 @@
                 return $wpsmiliestrans;
         }
+
+
+        /**
+         * Tests that the function does not throw a fatal error from count()
+         * when preg_split() fails on large input.
+         *
+         * @ticket 51019
+         */
+        public function test_smilies_with_large_text_input() {
+                $text = '<p><img alt="" src="data:image/png;base64,' . str_repeat( 'iVBORw0KGgoAAAAN', 65536 ) . '="></p> :)';
+                $this->assertStringContainsString( "\xf0\x9f\x99\x82", convert_smilies( $text ) );
+        }
 }