14.21.4 Security Considerations for the InnoDB memcached Plugin
Consult this section before deploying the
daemon_memcached plugin on a production server, or even on a test server if the MySQL instance contains sensitive data.
Because memcached does not use an authentication mechanism by default, and the optional SASL authentication is not as strong as traditional DBMS security measures, only keep non-sensitive data in the MySQL instance that uses the
daemon_memcached plugin, and wall off any servers that use this configuration from potential intruders. Do not allow memcached access to these servers from the Internet; only allow access from within a firewalled intranet, ideally from a subnet whose membership you can restrict.
SASL support provides the capability to protect your MySQL database from unauthenticated access through memcached clients. This section explains how to enable SASL with the
daemon_memcached plugin. The steps are almost identical to those performed to enabled SASL for a traditional memcached server.
SASL stands for “Simple Authentication and Security Layer”, a standard for adding authentication support to connection-based protocols. memcached added SASL support in version 1.4.3.
SASL authentication is only supported with the binary protocol.
memcached clients are only able to access
InnoDB tables that are registered in the
innodb_memcache.containers table. Even though a DBA can place access restrictions on such tables, access through memcached applications cannot be controlled. For this reason, SASL support is provided to control access to
InnoDB tables associated with the
The following section shows how to build, enable, and test an SASL-enabled
By default, an SASL-enabled
daemon_memcached plugin is not included in MySQL release packages, since an SASL-enabled
daemon_memcached plugin requires building memcached with SASL libraries. To enable SASL support, download the MySQL source and rebuild the
daemon_memcached plugin after downloading the SASL libraries:
Install the SASL development and utility libraries. For example, on Ubuntu, use apt-get to obtain the libraries:
sudo apt-get -f install libsasl2-2 sasl2-bin libsasl2-2 libsasl2-dev libsasl2-modules
daemon_memcachedplugin shared libraries with SASL capability by adding
ENABLE_MEMCACHED_SASL=1to your cmake options. memcached also provides simple cleartext password support, which facilitates testing. To enable simple cleartext password support, specify the
In summary, add following three cmake options:
cmake ... -DWITH_INNODB_MEMCACHED=1 -DENABLE_MEMCACHED_SASL=1 -DENABLE_MEMCACHED_SASL_PWDB=1
daemon_memcachedplugin, as described in Section 14.21.3, “Setting Up the InnoDB memcached Plugin”.
Configure a user name and password file. (This example uses memcached simple cleartext password support.)
In a file, create a user named
testnameand define the password as
echo "testname:testpasswd:::::::" >/home/jy/memcached-sasl-db
MEMCACHED_SASL_PWDBenvironment variable to inform
memcachedof the user name and password file:
memcachedthat a cleartext password is used:
echo "mech_list: plain" > /home/jy/work2/msasl/clients/memcached.conf export SASL_CONF_PATH=/home/jy/work2/msasl/clients
Enable SASL by restarting the MySQL server with the memcached
-Soption encoded in the
mysqld ... --daemon_memcached_option="-S"
To test the setup, use an SASL-enabled client such as SASL-enabled libmemcached .
memcp --servers=localhost:11211 --binary --username=testname --password=password myfile.txt memcat --servers=localhost:11211 --binary --username=testname --password=password myfile.txt
If you specify an incorrect user name or password, the operation is rejected with a
memcache error AUTHENTICATION FAILUREmessage. In this case, examine the cleartext password set in the
memcached-sasl-dbfile to verify that the credentials you supplied are correct.
There are other methods to test SASL authentication with memcached, but the method described above is the most straightforward.