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Docs: Adjust some DocBlocks in wpdb per the documentation standards.
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Includes:
* Wrapping long single-line comments to multi-line for better readability.
* Formatting code blocks to display correctly on the Code Reference.
* Other minor edits for consistency.

This applies to:
* `wpdb::$allow_unsafe_unquoted_parameters`
* `wpdb::escape_identifier()`
* `wpdb::_escape_identifier_value()`
* `wpdb::prepare()`
* `wpdb::has_cap()`

Follow-up to [53575].

See #52506, #55646.
Built from https://develop.svn.wordpress.org/trunk@53584


git-svn-id: https://core.svn.wordpress.org/trunk@53172 1a063a9b-81f0-0310-95a4-ce76da25c4cd
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@SergeyBiryukov
SergeyBiryukov committed Jun 28, 2022
1 parent 0aba666 commit 6b5d2f2
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Showing 2 changed files with 100 additions and 51 deletions.
2 changes: 1 addition & 1 deletion wp-includes/version.php
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Original file line number Diff line number Diff line change
Expand Up @@ -16,7 +16,7 @@
*
* @global string $wp_version
*/
$wp_version = '6.1-alpha-53582';
$wp_version = '6.1-alpha-53584';

/**
* Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.
Expand Down
149 changes: 99 additions & 50 deletions wp-includes/wp-db.php
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Original file line number Diff line number Diff line change
Expand Up @@ -645,27 +645,34 @@ class wpdb {
);

/**
* Backwards compatibility, where wpdb::prepare() has not quoted formatted/argnum placeholders.
* Backward compatibility, where wpdb::prepare() has not quoted formatted/argnum placeholders.
*
* Historically this could be used for table/field names, or for some string formatting, e.g.
* $wpdb->prepare( 'WHERE `%1s` = "%1s something %1s" OR %1$s = "%-10s"', 'field_1', 'a', 'b', 'c' );
*
* $wpdb->prepare( 'WHERE `%1s` = "%1s something %1s" OR %1$s = "%-10s"', 'field_1', 'a', 'b', 'c' );
*
* But it's risky, e.g. forgetting to add quotes, resulting in SQL Injection vulnerabilities:
* $wpdb->prepare( 'WHERE (id = %1s) OR (id = %2$s)', $_GET['id'], $_GET['id'] ); // ?id=id
*
* $wpdb->prepare( 'WHERE (id = %1s) OR (id = %2$s)', $_GET['id'], $_GET['id'] ); // ?id=id
*
* This feature is preserved while plugin authors update their code to use safer approaches:
* $wpdb->prepare( 'WHERE %1s = %s', $_GET['key'], $_GET['value'] );
* $wpdb->prepare( 'WHERE %i = %s', $_GET['key'], $_GET['value'] );
*
* $wpdb->prepare( 'WHERE %1s = %s', $_GET['key'], $_GET['value'] );
* $wpdb->prepare( 'WHERE %i = %s', $_GET['key'], $_GET['value'] );
*
* While changing to false will be fine for queries not using formatted/argnum placeholders,
* any remaining cases are most likely going to result in SQL errors (good, in a way):
* $wpdb->prepare( 'WHERE %1s = "%-10s"', 'my_field', 'my_value' );
*
* $wpdb->prepare( 'WHERE %1s = "%-10s"', 'my_field', 'my_value' );
* true = WHERE my_field = "my_value "
* false = WHERE 'my_field' = "'my_value '"
*
* But there may be some queries that result in an SQL Injection vulnerability:
* $wpdb->prepare( 'WHERE id = %1s', $_GET['id'] ); // ?id=id
* So there may need to be a `_doing_it_wrong()` phase, after we know everyone can use Identifier
* placeholders (%i), but before this feature is disabled or removed.
*
* $wpdb->prepare( 'WHERE id = %1s', $_GET['id'] ); // ?id=id
*
* So there may need to be a `_doing_it_wrong()` phase, after we know everyone can use
* identifier placeholders (%i), but before this feature is disabled or removed.
*
* @since 6.1.0
* @var bool
Expand Down Expand Up @@ -1376,31 +1383,31 @@ public function escape_by_ref( &$string ) {
}

/**
* Escapes an identifier for a MySQL database (e.g. table/field names).
* Escapes an identifier for a MySQL database, e.g. table/field names.
*
* @since 6.1.0
*
* @param string $identifier Identifier to escape.
* @return string Escaped Identifier
* @return string Escaped identifier.
*/
public function escape_identifier( $identifier ) {
return '`' . $this->_escape_identifier_value( $identifier ) . '`';
}

/**
* Escapes an identifier value.
*
* Escapes an identifier value without adding the surrounding quotes.
*
* - Permitted characters in quoted identifiers include the full Unicode Basic Multilingual Plane (BMP), except U+0000
* - To quote the identifier itself, then you need to double the character, e.g. `a``b`
* - Permitted characters in quoted identifiers include the full Unicode
* Basic Multilingual Plane (BMP), except U+0000.
* - To quote the identifier itself, you need to double the character, e.g. `a``b`.
*
* @link https://dev.mysql.com/doc/refman/8.0/en/identifiers.html
* @since 6.1.0
* @access private
*
* @link https://dev.mysql.com/doc/refman/8.0/en/identifiers.html
*
* @param string $identifier Identifier to escape.
* @return string Escaped Identifier
* @return string Escaped identifier.
*/
private function _escape_identifier_value( $identifier ) {
return str_replace( '`', '``', $identifier );
Expand Down Expand Up @@ -1433,17 +1440,24 @@ private function _escape_identifier_value( $identifier ) {
*
* 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' );
* $wpdb->prepare(
* "SELECT * FROM `table` WHERE `column` = %s AND `field` = %d OR `other_field` LIKE %s",
* array( 'foo', 1337, '%bar' )
* );
*
* $wpdb->prepare(
* "SELECT DATE_FORMAT(`field`, '%%c') FROM `table` WHERE `column` = %s",
* 'foo'
* );
*
* @since 2.3.0
* @since 5.3.0 Formalized the existing and already documented `...$args` parameter
* by updating the function signature. The second parameter was changed
* from `$args` to `...$args`.
* @since 6.1.0 Added '%i' for Identifiers, e.g. table or field names.
* Check support via `wpdb::has_cap( 'identifier_placeholders' )`
* This preserves compatibility with sprinf, as the C version uses %d and $i
* as a signed integer, whereas PHP only supports %d.
* @since 6.1.0 Added `%i` for identifiers, e.g. table or field names.
* Check support via `wpdb::has_cap( 'identifier_placeholders' )`.
* This preserves compatibility with sprintf(), as the C version uses
* `%d` and `$i` as a signed integer, whereas PHP only supports `%d`.
*
* @link https://www.php.net/sprintf Description of syntax.
*
Expand Down Expand Up @@ -1478,43 +1492,49 @@ public function prepare( $query, ...$args ) {
/*
* 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
* - Sign specifier, e.g. $+d
* - Numbered placeholders, e.g. %1$s
* - Padding specifier, including custom padding characters, e.g. %05s, %'#5s
* - Alignment specifier, e.g. %05-s
* - Precision specifier, e.g. %.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.
* If a %s placeholder already has quotes around it, removing the existing quotes
* and re-inserting them ensures the quotes are consistent.
*
* For backward compatibility, this is only applied to %s, and not to placeholders like %1$s, which are frequently
* used in the middle of longer strings, or as table name placeholders.
* For backward compatibility, this is only applied to %s, and not to placeholders like %1$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.

$query = preg_replace( "/%(?:%|$|(?!($allowed_format)?[sdfFi]))/", '%%\\1', $query ); // Escape any unescaped percents (i.e. anything unrecognised).
// Escape any unescaped percents (i.e. anything unrecognised).
$query = preg_replace( "/%(?:%|$|(?!($allowed_format)?[sdfFi]))/", '%%\\1', $query );

// Extract placeholders from the query.
$split_query = preg_split( "/(^|[^%]|(?:%%)+)(%(?:$allowed_format)?[sdfFi])/", $query, -1, PREG_SPLIT_DELIM_CAPTURE );

$split_query_count = count( $split_query );
$placeholder_count = ( ( $split_query_count - 1 ) / 3 ); // Split always returns with 1 value before the first placeholder (even with $query = "%s"), then 3 additional values per placeholder.
/*
* Split always returns with 1 value before the first placeholder (even with $query = "%s"),
* then 3 additional values per placeholder.
*/
$placeholder_count = ( ( $split_query_count - 1 ) / 3 );

// 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 = ( isset( $args[0] ) && is_array( $args[0] ) && 1 === count( $args ) );
if ( $passed_as_array ) {
$args = $args[0];
}

$new_query = '';
$key = 2; // keys 0 and 1 in $split_query contain values before the first placeholder.
$key = 2; // Keys 0 and 1 in $split_query contain values before the first placeholder.
$arg_id = 0;
$arg_identifiers = array();
$arg_strings = array();

while ( $key < $split_query_count ) {
$placeholder = $split_query[ $key ];

Expand All @@ -1528,30 +1548,44 @@ public function prepare( $query, ...$args ) {

if ( 'i' === $type ) {
$placeholder = '`%' . $format . 's`';
$argnum_pos = strpos( $format, '$' ); // Using a simple strpos() due to previous checking (e.g. $allowed_format).
// Using a simple strpos() due to previous checking (e.g. $allowed_format).
$argnum_pos = strpos( $format, '$' );

if ( false !== $argnum_pos ) {
$arg_identifiers[] = ( intval( substr( $format, 0, $argnum_pos ) ) - 1 ); // sprintf argnum starts at 1, $arg_id from 0.
// sprintf() argnum starts at 1, $arg_id from 0.
$arg_identifiers[] = ( intval( substr( $format, 0, $argnum_pos ) ) - 1 );
} else {
$arg_identifiers[] = $arg_id;
}
} elseif ( 'd' !== $type && 'F' !== $type ) { // i.e. ('s' === $type), where 'd' and 'F' keeps $placeholder unchanged, and we ensure string escaping is used as a safe default (e.g. even if 'x').
} elseif ( 'd' !== $type && 'F' !== $type ) {
/*
* i.e. ( 's' === $type ), where 'd' and 'F' keeps $placeholder unchanged,
* and we ensure string escaping is used as a safe default (e.g. even if 'x').
*/
$argnum_pos = strpos( $format, '$' );

if ( false !== $argnum_pos ) {
$arg_strings[] = ( intval( substr( $format, 0, $argnum_pos ) ) - 1 );
}
if ( true !== $this->allow_unsafe_unquoted_parameters || '' === $format ) { // Unquoted strings for backwards compatibility (dangerous).

// Unquoted strings for backward compatibility (dangerous).
if ( true !== $this->allow_unsafe_unquoted_parameters || '' === $format ) {
$placeholder = "'%" . $format . "s'";
}
}

$new_query .= $split_query[ $key - 2 ] . $split_query[ $key - 1 ] . $placeholder; // Glue (-2), any leading characters (-1), then the new $placeholder.
// Glue (-2), any leading characters (-1), then the new $placeholder.
$new_query .= $split_query[ $key - 2 ] . $split_query[ $key - 1 ] . $placeholder;

$key += 3;
$arg_id++;
}
$query = $new_query . $split_query[ $key - 2 ]; // Replace $query; and add remaining $query characters, or index 0 if there were no placeholders.

// Replace $query; and add remaining $query characters, or index 0 if there were no placeholders.
$query = $new_query . $split_query[ $key - 2 ];

$dual_use = array_intersect( $arg_identifiers, $arg_strings );

if ( count( $dual_use ) ) {
wp_load_translations_early();
_doing_it_wrong(
Expand All @@ -1571,7 +1605,10 @@ public function prepare( $query, ...$args ) {

if ( $args_count !== $placeholder_count ) {
if ( 1 === $placeholder_count && $passed_as_array ) {
// If the passed query only expected one argument, but the wrong number of arguments were sent as an array, bail.
/*
* If the passed query only expected one argument,
* but the wrong number of arguments was sent as an array, bail.
*/
wp_load_translations_early();
_doing_it_wrong(
'wpdb::prepare',
Expand All @@ -1582,7 +1619,8 @@ public function prepare( $query, ...$args ) {
return;
} else {
/*
* If we don't have the right number of placeholders, but they were passed as individual arguments,
* 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();
Expand All @@ -1603,12 +1641,16 @@ public function prepare( $query, ...$args ) {
*/
if ( $args_count < $placeholder_count ) {
$max_numbered_placeholder = 0;

for ( $i = 2, $l = $split_query_count; $i < $l; $i += 3 ) {
$argnum = intval( substr( $split_query[ $i ], 1 ) ); // Assume a leading number is for a numbered placeholder, e.g. '%3$s'.
// Assume a leading number is for a numbered placeholder, e.g. '%3$s'.
$argnum = intval( substr( $split_query[ $i ], 1 ) );

if ( $max_numbered_placeholder < $argnum ) {
$max_numbered_placeholder = $argnum;
}
}

if ( ! $max_numbered_placeholder || $args_count < $max_numbered_placeholder ) {
return '';
}
Expand All @@ -1635,8 +1677,11 @@ public function prepare( $query, ...$args ) {
),
'4.8.2'
);
$value = ''; // Preserving old behaviour, where values are escaped as strings.

// Preserving old behavior, where values are escaped as strings.
$value = '';
}

$args_escaped[] = $this->_real_escape( $value );
}
}
Expand Down Expand Up @@ -3872,11 +3917,11 @@ public function get_charset_collate() {
}

/**
* Determine DB or WPDB support for a particular feature.
* Determines whether the database or WPDB supports a particular feature.
*
* Capability sniffs for the database server and current version of wpdb.
* Capability sniffs for the database server and current version of WPDB.
*
* Database sniffs test based on the version of MySQL the site is using.
* Database sniffs are based on the version of MySQL the site is using.
*
* WPDB sniffs are added as new features are introduced to allow theme and plugin
* developers to determine feature support. This is to account for drop-ins which may
Expand Down Expand Up @@ -3926,7 +3971,11 @@ public function has_cap( $db_cap ) {
}
case 'utf8mb4_520': // @since 4.6.0
return version_compare( $version, '5.6', '>=' );
case 'identifier_placeholders': // @since 6.1.0, wpdb::prepare() supports identifiers via '%i' - e.g. table/field names.
case 'identifier_placeholders': // @since 6.1.0
/*
* As of WordPress 6.1, wpdb::prepare() supports identifiers via '%i',
* e.g. table/field names.
*/
return true;
}

Expand Down

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