Changeset 42056 for trunk/src/wp-includes/wp-db.php

Timestamp:

10/31/2017 11:59:43 AM (9 years ago)

Author:

pento

Message:

Database: Restore numbered placeholders in wpdb::prepare().

[41496] removed support for numbered placeholders in queries send through wpdb::prepare(), which, despite being undocumented, were quite commonly used.

This change restores support for numbered placeholders (as well as a subset of placeholder formatting), while also adding extra checks to ensure the correct number of arguments are being passed to wpdb::prepare(), given the number of placeholders.

See #41925.

File:

• trunk/src/wp-includes/wp-db.php (modified) (7 diffs)

trunk/src/wp-includes/wp-db.php

@@ -1107 +1107 @@
                 if ( $this->dbh ) {
                         if ( $this->use_mysqli ) {
-                                return mysqli_real_escape_string( $this->dbh, $string );
+                                $escaped = mysqli_real_escape_string( $this->dbh, $string );
                         } else {
-                                return mysql_real_escape_string( $string, $this->dbh );
-                        }
-                }
-
-                $class = get_class( $this );
-                if ( function_exists( '__' ) ) {
-                        /* translators: %s: database access abstraction class, usually wpdb or a class extending wpdb */
-                        _doing_it_wrong( $class, sprintf( __( '%s must set a database connection for use with escaping.' ), $class ), '3.6.0' );
+                                $escaped = mysql_real_escape_string( $string, $this->dbh );
+                        }
                 } else {
-                        _doing_it_wrong( $class, sprintf( '%s must set a database connection for use with escaping.', $class ), '3.6.0' );
-                }
-                return addslashes( $string );
+                        $class = get_class( $this );
+                        if ( function_exists( '__' ) ) {
+                                /* translators: %s: database access abstraction class, usually wpdb or a class extending wpdb */
+                                _doing_it_wrong( $class, sprintf( __( '%s must set a database connection for use with escaping.' ), $class ), '3.6.0' );
+                        } else {
+                                _doing_it_wrong( $class, sprintf( '%s must set a database connection for use with escaping.', $class ), '3.6.0' );
+                        }
+                        $escaped = addslashes( $string );
+                }
+
+                return $this->add_placeholder_escape( $escaped );
         }
 
@@ -1202 +1204 @@
          * All placeholders MUST be left unquoted in the query string. A corresponding argument MUST be passed for each placeholder.
          *
+         * For compatibility with old behavior, numbered or formatted string placeholders (eg, %1$s, %5s) will not have quotes
+         * added by this function, so should be passed with appropriate quotes around them for your usage.
+         *
          * Literal percentage signs (%) in the query string must be written as %%. Percentage wildcards (for example,
          * to use in LIKE syntax) must be passed via a substitution argument containing the complete LIKE string, these
          * cannot be inserted directly in the query string. Also see {@see esc_like()}.
          *
-         * This method DOES NOT support sign, padding, alignment, width or precision specifiers.
-         * This method DOES NOT support argument numbering or swapping.
-         *
-         * Arguments may be passed as individual arguments to the method, or as a single array containing all arguments. A combination 
+         * Arguments may be passed as individual arguments to the method, or as a single array containing all arguments. A combination
          * of the two is not supported.
          *
@@ -1226 +1228 @@
          */
         public function prepare( $query, $args ) {
-                if ( is_null( $query ) )
+                if ( is_null( $query ) ) {
                         return;
+                }
 
                 // This is not meant to be foolproof -- but it will catch obviously incorrect usage.
@@ -1238 +1241 @@
                 array_shift( $args );
 
-                // If args were passed as an array (as in vsprintf), move them up
+                // If args were passed as an array (as in vsprintf), move them up.
+                $passed_as_array = false;
                 if ( is_array( $args[0] ) && count( $args ) == 1 ) {
+                        $passed_as_array = true;
                         $args = $args[0];
                 }
@@ -1250 +1255 @@
                 }
 
-                $query = str_replace( "'%s'", '%s', $query ); // in case someone mistakenly already singlequoted it
-                $query = str_replace( '"%s"', '%s', $query ); // doublequote unquoting
-                $query = preg_replace( '|(?<!%)%f|' , '%F', $query ); // Force floats to be locale unaware
-                $query = preg_replace( '|(?<!%)%s|', "'%s'", $query ); // quote the strings, avoiding escaped strings like %%s
-                $query = preg_replace( '/%(?:%|$|([^dsF]))/', '%%\\1', $query ); // escape any unescaped percents
-
-                // Count the number of valid placeholders in the query
-                $placeholders = preg_match_all( '/(^|[^%]|(%%)+)%[sdF]/', $query, $matches );
-
-                if ( count ( $args ) !== $placeholders ) {
-                        wp_load_translations_early();
-                        _doing_it_wrong( 'wpdb::prepare',
-                                /* translators: 1: number of placeholders, 2: number of arguments passed */
-                                sprintf( __( 'The query does not contain the correct number of placeholders (%1$d) for the number of arguments passed (%2$d).' ),
-                                        $placeholders,
-                                        count( $args ) ),
-                                '4.9.0'
-                        );
+                /*
+                 * Specify the formatting allowed in a placeholder. The following are allowed:
+                 *
+                 * - Sign specifier. eg, $+d
+                 * - Numbered placeholders. eg, %1$s
+                 * - Padding specifier, including custom padding characters. eg, %05s, %'#5s
+                 * - Alignment specifier. eg, %05-s
+                 * - Precision specifier. eg, %.2f
+                 */
+                $allowed_format = '(?:[1-9][0-9]*[$])?[-+0-9]*(?: |0|\'.)?[-+0-9]*(?:\.[0-9]+)?';
+
+                /*
+                 * If a %s placeholder already has quotes around it, removing the existing quotes and re-inserting them
+                 * ensures the quotes are consistent.
+                 *
+                 * For backwards compatibility, this is only applied to %s, and not to placeholders like %1$s, which are frequently
+                 * used in the middle of longer strings, or as table name placeholders.
+                 */
+                $query = str_replace( "'%s'", '%s', $query ); // Strip any existing single quotes.
+                $query = str_replace( '"%s"', '%s', $query ); // Strip any existing double quotes.
+                $query = preg_replace( '/(?<!%)%s/', "'%s'", $query ); // Quote the strings, avoiding escaped strings like %%s.
+
+                $query = preg_replace( "/(?<!%)(%($allowed_format)?f)/" , '%\\2F', $query ); // Force floats to be locale unaware.
+
+                $query = preg_replace( "/%(?:%|$|(?!($allowed_format)?[sdF]))/", '%%\\1', $query ); // Escape any unescaped percents.
+
+                // Count the number of valid placeholders in the query.
+                $placeholders = preg_match_all( "/(^|[^%]|(%%)+)%($allowed_format)?[sdF]/", $query, $matches );
+
+                if ( count( $args ) !== $placeholders ) {
+                        if ( 1 === $placeholders && $passed_as_array ) {
+                                // If the passed query only expected one argument, but the wrong number of arguments were sent as an array, bail.
+                                wp_load_translations_early();
+                                _doing_it_wrong( 'wpdb::prepare', __( 'The query only expected one placeholder, but an array of multiple placeholders was sent.' ), '4.9.0' );
+
+                                return;
+                        } else {
+                                /*
+                                 * If we don't have the right number of placeholders, but they were passed as individual arguments,
+                                 * or we were expecting multiple arguments in an array, throw a warning.
+                                 */
+                                wp_load_translations_early();
+                                _doing_it_wrong( 'wpdb::prepare',
+                                        /* translators: 1: number of placeholders, 2: number of arguments passed */
+                                        sprintf( __( 'The query does not contain the correct number of placeholders (%1$d) for the number of arguments passed (%2$d).' ),
+                                                $placeholders,
+                                                count( $args ) ),
+                                        '4.8.3'
+                                );
+                        }
                 }
 
                 array_walk( $args, array( $this, 'escape_by_ref' ) );
-                return @vsprintf( $query, $args );
+                $query = @vsprintf( $query, $args );
+
+                return $this->add_placeholder_escape( $query );
         }
 
@@ -1892 +1931 @@
                         $this->queries[] = array( $query, $this->timer_stop(), $this->get_caller() );
                 }
+        }
+
+        /**
+         * Generates and returns a placeholder escape string for use in queries returned by ::prepare().
+         *
+         * @since 4.8.3
+         *
+         * @return string String to escape placeholders.
+         */
+        public function placeholder_escape() {
+                static $placeholder;
+
+                if ( ! $placeholder ) {
+                        // If ext/hash is not present, compat.php's hash_hmac() does not support sha256.
+                        $algo = function_exists( 'hash' ) ? 'sha256' : 'sha1';
+                        // Old WP installs may not have AUTH_SALT defined.
+                        $salt = defined( 'AUTH_SALT' ) ? AUTH_SALT : rand();
+
+                        $placeholder = '{' . hash_hmac( $algo, uniqid( $salt, true ), $salt ) . '}';
+                }
+
+                /*
+                 * Add the filter to remove the placeholder escaper. Uses priority 0, so that anything
+                 * else attached to this filter will recieve the query with the placeholder string removed.
+                 */
+                if ( ! has_filter( 'query', array( $this, 'remove_placeholder_escape' ) ) ) {
+                        add_filter( 'query', array( $this, 'remove_placeholder_escape' ), 0 );
+                }
+
+                return $placeholder;
+        }
+
+        /**
+         * Adds a placeholder escape string, to escape anything that resembles a printf() placeholder.
+         *
+         * @since 4.8.3
+         *
+         * @param string $query The query to escape.
+         * @return string The query with the placeholder escape string inserted where necessary.
+         */
+        public function add_placeholder_escape( $query ) {
+                /*
+                 * To prevent returning anything that even vaguely resembles a placeholder,
+                 * we clobber every % we can find.
+                 */
+                return str_replace( '%', $this->placeholder_escape(), $query );
+        }
+
+        /**
+         * Removes the placeholder escape strings from a query.
+         *
+         * @since 4.8.3
+         *
+         * @param string $query The query from which the placeholder will be removed.
+         * @return string The query with the placeholder removed.
+         */
+        public function remove_placeholder_escape( $query ) {
+                return str_replace( $this->placeholder_escape(), '%', $query );
         }
 
@@ -2065 +2162 @@
 
                 $sql = "UPDATE `$table` SET $fields WHERE $conditions";
-                
+
                 $this->check_current_query = false;
                 return $this->query( $this->prepare( $sql, $values ) );