The mysqlnd user handler plugin (mysqlnd_uh
)
allows users to set hooks for most internal calls of the
MySQL native driver for PHP
(mysqlnd
).
Mysqlnd and its plugins, including PECL/mysqlnd_uh, operate on a layer
beneath the PHP MySQL extensions. A mysqlnd plugin can be considered
as a proxy between the PHP MySQL extensions and the MySQL server
as part of the PHP executable on the client-side. Because the plugins
operates on their own layer below the PHP MySQL extensions,
they can monitor and change application actions without requiring
application changes. If the
PHP MySQL extensions (mysqli,
mysql,
PDO_MYSQL) are compiled to
use mysqlnd
this can be used for:
Monitoring
Queries executed by any of the PHP MySQL extensions
Prepared statements executing by any of the PHP MySQL extensions
Auditing
Detection of database usage
SQL injection protection using black and white lists
Assorted
Load Balancing connections
The MySQL native driver for PHP (mysqlnd) features an internal plugin C API. C plugins, such as the mysqlnd user handler plugin, can extend the functionality of mysqlnd. PECL/mysqlnd_uh makes parts of the internal plugin C API available to the PHP user for plugin development with PHP.
Notă: Status
The mysqlnd user handler plugin is in alpha status. Take appropriate care before using it in production environments.
PECL/mysqlnd_uh gives users access to MySQL user names, MySQL password
used by any of the PHP MySQL extensions to connect to MySQL.
It allows monitoring of all queries and prepared statements exposing
the statement string to the user. Therefore, the extension should be
installed with care. The PHP_INI_SYSTEM
configuration setting
mysqlnd_uh.enable
can be used to prevent users from hooking mysqlnd calls.
Code obfuscators and similar technologies are not suitable to prevent monitoring of mysqlnd library activities if PECL/mysqlnd_uh is made available and the user can install a proxy, for example, using auto_prepend_file.
Many of the mysqlnd_uh functions are briefly described because
the mysqli extension is
a thin abstraction layer on top of the MySQL C API that
the mysqlnd
library provides. Therefore,
the corresponding mysqli documentation
(along with the MySQL reference manual) can be consulted
to receive more information about a particular function.
The shortcut mysqlnd_uh
stands for
mysqlnd user handler
, and has been the name
since early development.