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Database: Restore numbered placeholders in wpdb::prepare().
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[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 3.9 branch.
See #41925.


Built from https://develop.svn.wordpress.org/branches/3.9@42066


git-svn-id: http://core.svn.wordpress.org/branches/3.9@41895 1a063a9b-81f0-0310-95a4-ce76da25c4cd
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@pento
pento committed Oct 31, 2017
1 parent ee47cb6 commit 9b92304
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Showing 2 changed files with 156 additions and 41 deletions.
4 changes: 2 additions & 2 deletions wp-includes/post.php
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Expand Up @@ -3903,10 +3903,10 @@ 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;
Expand Down
193 changes: 154 additions & 39 deletions wp-includes/wp-db.php
View file
Expand Up @@ -1073,15 +1073,22 @@ 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 );
}
} else {
$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 );
}

$class = get_class( $this );
_doing_it_wrong( $class, "$class must set a database connection for use with escaping.", E_USER_NOTICE );
return addslashes( $string );
return $this->add_placeholder_escape( $escaped );
}

/**
Expand Down Expand Up @@ -1155,70 +1162,120 @@ function escape_by_ref( &$string ) {
/**
* Prepares a SQL query for safe execution. Uses sprintf()-like syntax.
*
* The following directives can be used in the query format string:
* The following placeholders can be used in the query string:
* %d (integer)
* %f (float)
* %s (string)
* %% (literal percentage sign - no argument needed)
*
* All of %d, %f, and %s are to be left unquoted in the query string and they need an argument passed for them.
* Literals (%) as parts of the query must be properly written as %%.
* All placeholders MUST be left unquoted in the query string. A corresponding argument MUST be passed for each placeholder.
*
* This function only supports a small subset of the sprintf syntax; it only supports %d (integer), %f (float), and %s (string).
* Does not support sign, padding, alignment, width or precision specifiers.
* Does not support argument numbering/swapping.
* For compatibility with old behavior, numbered or formatted string placeholders (eg, %1$s, %5s) will not have quotes
* added by this function, so should be passed with appropriate quotes around them for your usage.
*
* May be called like {@link http://php.net/sprintf sprintf()} or like {@link http://php.net/vsprintf vsprintf()}.
* 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()}.
*
* Both %d and %s should be left unquoted in the query string.
* 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.
*
* <code>
* wpdb::prepare( "SELECT * FROM `table` WHERE `column` = %s AND `field` = %d", 'foo', 1337 )
* wpdb::prepare( "SELECT DATE_FORMAT(`field`, '%%c') FROM `table` WHERE `column` = %s", 'foo' );
* </code>
* 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' );
*
* @link http://php.net/sprintf Description of syntax.
* @link https://secure.php.net/sprintf Description of syntax.
* @since 2.3.0
*
* @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 http://php.net/vsprintf vsprintf()}, or the first variable to substitute into the query's placeholders if
* being called like {@link http://php.net/sprintf sprintf()}.
* @param mixed $args,... further variables to substitute into the query's placeholders if being called like
* {@link http://php.net/sprintf sprintf()}.
* @return null|false|string Sanitized query string, null if there is no query, false if there is an error and string
* if there was something to prepare
*/
function prepare( $query, $args ) {
if ( is_null( $query ) )
* @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 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 ) ) {
return;
}

// This is not meant to be foolproof -- but it will catch obviously incorrect usage.
if ( strpos( $query, '%' ) === false ) {
_doing_it_wrong( 'wpdb::prepare', sprintf( __( 'The query argument of %s must have a placeholder.' ), 'wpdb::prepare()' ), '3.9' );
wp_load_translations_early();
_doing_it_wrong( 'wpdb::prepare', sprintf( __( 'The query argument of %s must have a placeholder.' ), 'wpdb::prepare()' ), '3.9.0' );
}

$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];
}

foreach ( $args as $arg ) {
if ( ! is_scalar( $arg ) && ! is_null( $arg ) ) {
_doing_it_wrong( 'wpdb::prepare', sprintf( 'Unsupported value type (%s).', gettype( $arg ) ), '3.9.20' );
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'
);
}
}

$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
array_walk( $args, array( $this, 'escape_by_ref' ) );
return @vsprintf( $query, $args );
$query = @vsprintf( $query, $args );

return $this->add_placeholder_escape( $query );
}

/**
Expand Down Expand Up @@ -1696,6 +1753,64 @@ 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.
*
Expand Down

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