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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.


Built from https://develop.svn.wordpress.org/trunk@42056


git-svn-id: http://core.svn.wordpress.org/trunk@41885 1a063a9b-81f0-0310-95a4-ce76da25c4cd
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pento committed Oct 31, 2017
1 parent 6f2db8e commit a2693fd8602e3263b5925b9d799ddd577202167d
Showing with 142 additions and 41 deletions.
  1. +5 −0 wp-includes/formatting.php
  2. +3 −4 wp-includes/meta.php
  3. +2 −2 wp-includes/post.php
  4. +1 −1 wp-includes/version.php
  5. +131 −34 wp-includes/wp-db.php
@@ -3754,6 +3754,11 @@ function _deep_replace( $search, $subject ) {
* Sometimes, spot-escaping is required or useful. One example
* is preparing an array for use in an IN clause.
*
* NOTE: Since 4.8.3, '%' characters will be replaced with a placeholder string,
* this prevents certain SQLi attacks from taking place. This change in behaviour
* may cause issues for code that expects the return value of esc_sql() to be useable
* for other purposes.
*
* @since 2.8.0
*
* @global wpdb $wpdb WordPress database abstraction object.
@@ -364,12 +364,11 @@ function delete_metadata($meta_type, $object_id, $meta_key, $meta_value = '', $d
return false;
if ( $delete_all ) {
$value_clause = '';
if ( '' !== $meta_value && null !== $meta_value && false !== $meta_value ) {
$value_clause = $wpdb->prepare( " AND meta_value = %s", $meta_value );
$object_ids = $wpdb->get_col( $wpdb->prepare( "SELECT $type_column FROM $table WHERE meta_key = %s AND meta_value = %s", $meta_key, $meta_value ) );
} else {
$object_ids = $wpdb->get_col( $wpdb->prepare( "SELECT $type_column FROM $table WHERE meta_key = %s", $meta_key ) );
}
$object_ids = $wpdb->get_col( $wpdb->prepare( "SELECT $type_column FROM $table WHERE meta_key = %s $value_clause", $meta_key ) );
}
/**
@@ -4317,10 +4317,10 @@ function get_page_by_path( $page_path, $output = OBJECT, $post_type = 'page' ) {
$page_path = str_replace('%2F', '/', $page_path);
$page_path = str_replace('%20', ' ', $page_path);
$parts = explode( '/', trim( $page_path, '/' ) );
$parts = esc_sql( $parts );
$parts = array_map( 'sanitize_title_for_query', $parts );
$escaped_parts = esc_sql( $parts );
$in_string = "'" . implode( "','", $parts ) . "'";
$in_string = "'" . implode( "','", $escaped_parts ) . "'";
if ( is_array( $post_type ) ) {
$post_types = $post_type;
@@ -4,7 +4,7 @@
*
* @global string $wp_version
*/
$wp_version = '4.9-RC1-42050';
$wp_version = '4.9-RC1-42056';
/**
* Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.
@@ -1106,20 +1106,22 @@ function _weak_escape( $string ) {
function _real_escape( $string ) {
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 );
$escaped = 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' );
} else {
_doing_it_wrong( $class, sprintf( '%s must set a database connection for use with escaping.', $class ), '3.6.0' );
$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 addslashes( $string );
return $this->add_placeholder_escape( $escaped );
}
/**
@@ -1201,14 +1203,14 @@ public function escape_by_ref( &$string ) {
*
* 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$s, %5s) will not have quotes
* added by this function, so should be passed with appropriate quotes around them for your usage.
*
* Literal percentage signs (%) in the query string must be written as %%. Percentage wildcards (for example,
* to use in LIKE syntax) must be passed via a substitution argument containing the complete LIKE string, these
* cannot be inserted directly in the query string. Also see {@see esc_like()}.
*
* This method DOES NOT support sign, padding, alignment, width or precision specifiers.
* This method DOES NOT support argument numbering or swapping.
*
* Arguments may be passed as individual arguments to the method, or as a single array containing all arguments. A combination
* Arguments may be passed as individual arguments to the method, or as a single array containing all arguments. A combination
* of the two is not supported.
*
* Examples:
@@ -1225,8 +1227,9 @@ public function escape_by_ref( &$string ) {
* @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 ) {
@@ -1237,8 +1240,10 @@ public function prepare( $query, $args ) {
$args = func_get_args();
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];
}
@@ -1249,28 +1254,62 @@ public function prepare( $query, $args ) {
}
}
$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
/*
* 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.
// Count the number of valid placeholders in the query
$placeholders = preg_match_all( '/(^|[^%]|(%%)+)%[sdF]/', $query, $matches );
$query = preg_replace( "/%(?:%|$|(?!($allowed_format)?[sdF]))/", '%%\\1', $query ); // Escape any unescaped percents.
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'
);
// 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 );
}
/**
@@ -1893,6 +1932,64 @@ private function _do_query( $query ) {
}
}
/**
* 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 );
}
/**
* Insert a row into a table.
*
@@ -2064,7 +2161,7 @@ public function update( $table, $data, $where, $format = null, $where_format = n
$conditions = implode( ' AND ', $conditions );
$sql = "UPDATE `$table` SET $fields WHERE $conditions";
$this->check_current_query = false;
return $this->query( $this->prepare( $sql, $values ) );
}

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