Changeset 42057 for branches/4.8/src/wp-includes/wp-db.php

Timestamp:

10/31/2017 12:22:07 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 4.8 branch.
See #41925.

Location:

branches/4.8

Files:

• . (modified) (1 prop)
• src/wp-includes/wp-db.php (modified) (6 diffs)

branches/4.8/src/wp-includes/wp-db.php

@@ -1169 +1169 @@
         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 );
     }
 
@@ -1258 +1260 @@
      * Prepares a SQL query for safe execution. Uses sprintf()-like syntax.
      *
-     * The following directives can be used in the query format string:
+     * The following placeholders can be used in the query string:
      *   %d (integer)
      *   %f (float)
      *   %s (string)
-     *   %% (literal percentage sign - no argument needed)
-     *
-     * All of %d, %f, and %s are to be left unquoted in the query string and they need an argument passed for them.
-     * Literals (%) as parts of the query must be properly written as %%.
-     *
-     * This function only supports a small subset of the sprintf syntax; it only supports %d (integer), %f (float), and %s (string).
-     * Does not support sign, padding, alignment, width or precision specifiers.
-     * Does not support argument numbering/swapping.
-     *
-     * May be called like {@link https://secure.php.net/sprintf sprintf()} or like {@link https://secure.php.net/vsprintf vsprintf()}.
-     *
-     * Both %d and %s should be left unquoted in the query string.
-     *
-     *     $wpdb->prepare( "SELECT * FROM `table` WHERE `column` = %s AND `field` = %d", 'foo', 1337 );
+     *
+     * All placeholders MUST be left unquoted in the query string. A corresponding argument MUST be passed for each placeholder.
+     *
+     * For compatibility with old behavior, numbered or formatted string placeholders (eg, %1$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()}.
+     *
+     * 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.
+     *
+     * Examples:
+     *     $wpdb->prepare( "SELECT * FROM `table` WHERE `column` = %s AND `field` = %d OR `other_field` LIKE %s", array( 'foo', 1337, '%bar' ) );
      *     $wpdb->prepare( "SELECT DATE_FORMAT(`field`, '%%c') FROM `table` WHERE `column` = %s", 'foo' );
      *
@@ -1282 +1285 @@
      *
      * @param string      $query    Query statement with sprintf()-like placeholders
-     * @param array|mixed $args     The array of variables to substitute into the query's placeholders if being called like
-     *                              {@link https://secure.php.net/vsprintf vsprintf()}, or the first variable to substitute into the query's placeholders if
-     *                              being called like {@link https://secure.php.net/sprintf sprintf()}.
-     * @param mixed       $args,... further variables to substitute into the query's placeholders if being called like
-     *                              {@link https://secure.php.net/sprintf sprintf()}.
+     * @param array|mixed $args     The array of variables to substitute into the query's placeholders if being called with an array of arguments,
+     *                              or the first variable to substitute into the query's placeholders if being called with individual arguments.
+     * @param mixed       $args,... further variables to substitute into the query's placeholders if being called wih individual arguments.
      * @return string|void Sanitized query string, if there is a query to prepare.
      */
     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.
         if ( strpos( $query, '%' ) === false ) {
+            wp_load_translations_early();
             _doing_it_wrong( 'wpdb::prepare', sprintf( __( 'The query argument of %s must have a placeholder.' ), 'wpdb::prepare()' ), '3.9.0' );
         }
@@ -1301 +1304 @@
         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];
         }
@@ -1308 +1313 @@
         foreach ( $args as $arg ) {
             if ( ! is_scalar( $arg ) && ! is_null( $arg ) ) {
-                _doing_it_wrong( 'wpdb::prepare', sprintf( 'Unsupported value type (%s).', gettype( $arg ) ), '4.8.2' );
-            }
-        }
-
-        $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 
+                wp_load_translations_early();
+                _doing_it_wrong( 'wpdb::prepare', sprintf( __( 'Unsupported value type (%s).' ), gettype( $arg ) ), '4.8.2' );
+            }
+        }
+
+        /*
+         * 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 );
     }
 
@@ -1894 +1949 @@
             $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 );
     }