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Ignore:
Timestamp:
10/31/2017 12:40:24 PM (7 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.

Merges [41662], [42056] to the 4.6 branch.
See #41925.

Location:
branches/4.6
Files:
2 edited

Legend:

Unmodified
Added
Removed
  • branches/4.6

  • branches/4.6/src/wp-includes/wp-db.php

    r41499 r42059  
    11691169        if ( $this->dbh ) {
    11701170            if ( $this->use_mysqli ) {
    1171                 return mysqli_real_escape_string( $this->dbh, $string );
     1171                $escaped = mysqli_real_escape_string( $this->dbh, $string );
    11721172            } else {
    1173                 return mysql_real_escape_string( $string, $this->dbh );
    1174             }
    1175         }
    1176 
    1177         $class = get_class( $this );
    1178         if ( function_exists( '__' ) ) {
    1179             /* translators: %s: database access abstraction class, usually wpdb or a class extending wpdb */
    1180             _doing_it_wrong( $class, sprintf( __( '%s must set a database connection for use with escaping.' ), $class ), '3.6.0' );
     1173                $escaped = mysql_real_escape_string( $string, $this->dbh );
     1174            }
    11811175        } else {
    1182             _doing_it_wrong( $class, sprintf( '%s must set a database connection for use with escaping.', $class ), '3.6.0' );
    1183         }
    1184         return addslashes( $string );
     1176            $class = get_class( $this );
     1177            if ( function_exists( '__' ) ) {
     1178                /* translators: %s: database access abstraction class, usually wpdb or a class extending wpdb */
     1179                _doing_it_wrong( $class, sprintf( __( '%s must set a database connection for use with escaping.' ), $class ), '3.6.0' );
     1180            } else {
     1181                _doing_it_wrong( $class, sprintf( '%s must set a database connection for use with escaping.', $class ), '3.6.0' );
     1182            }
     1183            $escaped = addslashes( $string );
     1184        }
     1185
     1186        return $this->add_placeholder_escape( $escaped );
    11851187    }
    11861188
     
    12571259     * Prepares a SQL query for safe execution. Uses sprintf()-like syntax.
    12581260     *
    1259      * The following directives can be used in the query format string:
     1261     * The following placeholders can be used in the query string:
    12601262     *   %d (integer)
    12611263     *   %f (float)
    12621264     *   %s (string)
    1263      *   %% (literal percentage sign - no argument needed)
    1264      *
    1265      * All of %d, %f, and %s are to be left unquoted in the query string and they need an argument passed for them.
    1266      * Literals (%) as parts of the query must be properly written as %%.
    1267      *
    1268      * This function only supports a small subset of the sprintf syntax; it only supports %d (integer), %f (float), and %s (string).
    1269      * Does not support sign, padding, alignment, width or precision specifiers.
    1270      * Does not support argument numbering/swapping.
    1271      *
    1272      * May be called like {@link https://secure.php.net/sprintf sprintf()} or like {@link https://secure.php.net/vsprintf vsprintf()}.
    1273      *
    1274      * Both %d and %s should be left unquoted in the query string.
    1275      *
    1276      *     wpdb::prepare( "SELECT * FROM `table` WHERE `column` = %s AND `field` = %d", 'foo', 1337 )
    1277      *     wpdb::prepare( "SELECT DATE_FORMAT(`field`, '%%c') FROM `table` WHERE `column` = %s", 'foo' );
     1265     *
     1266     * All placeholders MUST be left unquoted in the query string. A corresponding argument MUST be passed for each placeholder.
     1267     *
     1268     * For compatibility with old behavior, numbered or formatted string placeholders (eg, %1$s, %5s) will not have quotes
     1269     * added by this function, so should be passed with appropriate quotes around them for your usage.
     1270     *
     1271     * Literal percentage signs (%) in the query string must be written as %%. Percentage wildcards (for example,
     1272     * to use in LIKE syntax) must be passed via a substitution argument containing the complete LIKE string, these
     1273     * cannot be inserted directly in the query string. Also see {@see esc_like()}.
     1274     *
     1275     * Arguments may be passed as individual arguments to the method, or as a single array containing all arguments. A combination
     1276     * of the two is not supported.
     1277     *
     1278     * Examples:
     1279     *     $wpdb->prepare( "SELECT * FROM `table` WHERE `column` = %s AND `field` = %d OR `other_field` LIKE %s", array( 'foo', 1337, '%bar' ) );
     1280     *     $wpdb->prepare( "SELECT DATE_FORMAT(`field`, '%%c') FROM `table` WHERE `column` = %s", 'foo' );
    12781281     *
    12791282     * @link https://secure.php.net/sprintf Description of syntax.
     
    12811284     *
    12821285     * @param string      $query    Query statement with sprintf()-like placeholders
    1283      * @param array|mixed $args     The array of variables to substitute into the query's placeholders if being called like
    1284      *                              {@link https://secure.php.net/vsprintf vsprintf()}, or the first variable to substitute into the query's placeholders if
    1285      *                              being called like {@link https://secure.php.net/sprintf sprintf()}.
    1286      * @param mixed       $args,... further variables to substitute into the query's placeholders if being called like
    1287      *                              {@link https://secure.php.net/sprintf sprintf()}.
     1286     * @param array|mixed $args     The array of variables to substitute into the query's placeholders if being called with an array of arguments,
     1287     *                              or the first variable to substitute into the query's placeholders if being called with individual arguments.
     1288     * @param mixed       $args,... further variables to substitute into the query's placeholders if being called wih individual arguments.
    12881289     * @return string|void Sanitized query string, if there is a query to prepare.
    12891290     */
    12901291    public function prepare( $query, $args ) {
    1291         if ( is_null( $query ) )
     1292        if ( is_null( $query ) ) {
    12921293            return;
     1294        }
    12931295
    12941296        // This is not meant to be foolproof -- but it will catch obviously incorrect usage.
    12951297        if ( strpos( $query, '%' ) === false ) {
     1298            wp_load_translations_early();
    12961299            _doing_it_wrong( 'wpdb::prepare', sprintf( __( 'The query argument of %s must have a placeholder.' ), 'wpdb::prepare()' ), '3.9.0' );
    12971300        }
     
    13001303        array_shift( $args );
    13011304
    1302         // If args were passed as an array (as in vsprintf), move them up
     1305        // If args were passed as an array (as in vsprintf), move them up.
     1306        $passed_as_array = false;
    13031307        if ( is_array( $args[0] ) && count( $args ) == 1 ) {
     1308            $passed_as_array = true;
    13041309            $args = $args[0];
    13051310        }
     
    13071312        foreach ( $args as $arg ) {
    13081313            if ( ! is_scalar( $arg ) && ! is_null( $arg ) ) {
    1309                 _doing_it_wrong( 'wpdb::prepare', sprintf( 'Unsupported value type (%s).', gettype( $arg ) ), '4.6.7' );
    1310             }
    1311         }
    1312 
    1313         $query = str_replace( "'%s'", '%s', $query ); // in case someone mistakenly already singlequoted it
    1314         $query = str_replace( '"%s"', '%s', $query ); // doublequote unquoting
    1315         $query = preg_replace( '|(?<!%)%f|' , '%F', $query ); // Force floats to be locale unaware
    1316         $query = preg_replace( '|(?<!%)%s|', "'%s'", $query ); // quote the strings, avoiding escaped strings like %%s
    1317         $query = preg_replace( '/%(?:%|$|([^dsF]))/', '%%\\1', $query ); // escape any unescaped percents
     1314                wp_load_translations_early();
     1315                _doing_it_wrong( 'wpdb::prepare', sprintf( __( 'Unsupported value type (%s).' ), gettype( $arg ) ), '4.8.2' );
     1316            }
     1317        }
     1318
     1319        /*
     1320         * Specify the formatting allowed in a placeholder. The following are allowed:
     1321         *
     1322         * - Sign specifier. eg, $+d
     1323         * - Numbered placeholders. eg, %1$s
     1324         * - Padding specifier, including custom padding characters. eg, %05s, %'#5s
     1325         * - Alignment specifier. eg, %05-s
     1326         * - Precision specifier. eg, %.2f
     1327         */
     1328        $allowed_format = '(?:[1-9][0-9]*[$])?[-+0-9]*(?: |0|\'.)?[-+0-9]*(?:\.[0-9]+)?';
     1329
     1330        /*
     1331         * If a %s placeholder already has quotes around it, removing the existing quotes and re-inserting them
     1332         * ensures the quotes are consistent.
     1333         *
     1334         * For backwards compatibility, this is only applied to %s, and not to placeholders like %1$s, which are frequently
     1335         * used in the middle of longer strings, or as table name placeholders.
     1336         */
     1337        $query = str_replace( "'%s'", '%s', $query ); // Strip any existing single quotes.
     1338        $query = str_replace( '"%s"', '%s', $query ); // Strip any existing double quotes.
     1339        $query = preg_replace( '/(?<!%)%s/', "'%s'", $query ); // Quote the strings, avoiding escaped strings like %%s.
     1340
     1341        $query = preg_replace( "/(?<!%)(%($allowed_format)?f)/" , '%\\2F', $query ); // Force floats to be locale unaware.
     1342
     1343        $query = preg_replace( "/%(?:%|$|(?!($allowed_format)?[sdF]))/", '%%\\1', $query ); // Escape any unescaped percents.
     1344
     1345        // Count the number of valid placeholders in the query.
     1346        $placeholders = preg_match_all( "/(^|[^%]|(%%)+)%($allowed_format)?[sdF]/", $query, $matches );
     1347
     1348        if ( count( $args ) !== $placeholders ) {
     1349            if ( 1 === $placeholders && $passed_as_array ) {
     1350                // If the passed query only expected one argument, but the wrong number of arguments were sent as an array, bail.
     1351                wp_load_translations_early();
     1352                _doing_it_wrong( 'wpdb::prepare', __( 'The query only expected one placeholder, but an array of multiple placeholders was sent.' ), '4.9.0' );
     1353
     1354                return;
     1355            } else {
     1356                /*
     1357                 * If we don't have the right number of placeholders, but they were passed as individual arguments,
     1358                 * or we were expecting multiple arguments in an array, throw a warning.
     1359                 */
     1360                wp_load_translations_early();
     1361                _doing_it_wrong( 'wpdb::prepare',
     1362                    /* translators: 1: number of placeholders, 2: number of arguments passed */
     1363                    sprintf( __( 'The query does not contain the correct number of placeholders (%1$d) for the number of arguments passed (%2$d).' ),
     1364                        $placeholders,
     1365                        count( $args ) ),
     1366                    '4.8.3'
     1367                );
     1368            }
     1369        }
     1370
    13181371        array_walk( $args, array( $this, 'escape_by_ref' ) );
    1319         return @vsprintf( $query, $args );
     1372        $query = @vsprintf( $query, $args );
     1373
     1374        return $this->add_placeholder_escape( $query );
    13201375    }
    13211376
     
    18901945            $this->queries[] = array( $query, $this->timer_stop(), $this->get_caller() );
    18911946        }
     1947    }
     1948
     1949    /**
     1950     * Generates and returns a placeholder escape string for use in queries returned by ::prepare().
     1951     *
     1952     * @since 4.8.3
     1953     *
     1954     * @return string String to escape placeholders.
     1955     */
     1956    public function placeholder_escape() {
     1957        static $placeholder;
     1958
     1959        if ( ! $placeholder ) {
     1960            // If ext/hash is not present, compat.php's hash_hmac() does not support sha256.
     1961            $algo = function_exists( 'hash' ) ? 'sha256' : 'sha1';
     1962            // Old WP installs may not have AUTH_SALT defined.
     1963            $salt = defined( 'AUTH_SALT' ) ? AUTH_SALT : rand();
     1964
     1965            $placeholder = '{' . hash_hmac( $algo, uniqid( $salt, true ), $salt ) . '}';
     1966        }
     1967
     1968        /*
     1969         * Add the filter to remove the placeholder escaper. Uses priority 0, so that anything
     1970         * else attached to this filter will recieve the query with the placeholder string removed.
     1971         */
     1972        if ( ! has_filter( 'query', array( $this, 'remove_placeholder_escape' ) ) ) {
     1973            add_filter( 'query', array( $this, 'remove_placeholder_escape' ), 0 );
     1974        }
     1975
     1976        return $placeholder;
     1977    }
     1978
     1979    /**
     1980     * Adds a placeholder escape string, to escape anything that resembles a printf() placeholder.
     1981     *
     1982     * @since 4.8.3
     1983     *
     1984     * @param string $query The query to escape.
     1985     * @return string The query with the placeholder escape string inserted where necessary.
     1986     */
     1987    public function add_placeholder_escape( $query ) {
     1988        /*
     1989         * To prevent returning anything that even vaguely resembles a placeholder,
     1990         * we clobber every % we can find.
     1991         */
     1992        return str_replace( '%', $this->placeholder_escape(), $query );
     1993    }
     1994
     1995    /**
     1996     * Removes the placeholder escape strings from a query.
     1997     *
     1998     * @since 4.8.3
     1999     *
     2000     * @param string $query The query from which the placeholder will be removed.
     2001     * @return string The query with the placeholder removed.
     2002     */
     2003    public function remove_placeholder_escape( $query ) {
     2004        return str_replace( $this->placeholder_escape(), '%', $query );
    18922005    }
    18932006
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